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DISTRIBUTED BY INTERAGENCY RESOURCES DIVISION, WASH I N G T O N, D. C.
WHAT IS
THE NATIONAL HISTORIC PRESERVATION ACT?
The National Historic Preservation Act of 1966, as amended (16 U.S.C. 470) is the nation's
central historic preservation law. It establishes the legal and administrative context within
which local historic preservation commissions relate to, and participate in, the national historic
preservation program.
Passed at a time when Americans were becoming increasingly aware of the damage being done
to their heritalip by modern development, and strengthened and elaborated upon several times
since, the Act is designed to encourage preservation and wise use of our historic resources. The
Act does several important things:
National Policy: The Act sets forth the policy of the U.S. Government regarding historic
preservation. In a nutshell, the policy is to promote conditions in which historic properties can
be preserved in harmony with modern society, and fulfill modern society's needs.
The National Register: The Act authorizes the Department of the Interior to establish,
maintain, and expand a National Register of Historic Places. The Register is maintained by the
National Park Service; it is a computerized listing of properties that have been nominated and
accepted as having historic, architectural, archeological, engineering or cultural significance, at
the national, State, or local level. The Register is growing steadily as more properties are
identified and nominated each year (See "What are the National Register Criteria?").
The SHPO: The Act establishes the responsibilities of State Historic Preservation Officers, or
"SHPO's," the State officials who administer the national historic preservation program at the
State level. Each SHPO is responsible for developing a statewide plan for preservation,
surveying to identify historic properties, nominating properties to the National Register,
providing technical assistance to Federal, State, and local agencies and the public, participating
in the review of Federal undertakings that affect historic properties, helping local governments
become certified to participate in the program, and other activities (See"What is a SHPO?).
Grants-in-Aid: The Act establishes a program of matching grants-in-aid by which the National
Park Service assists the SHPO's in carrying out their work. SHPO's may subgrant portions of
these funds to local governments and others for approved preservation projects.
Certified Local Governments: The Act provides for the certification of local
governments whose historic preservation programs meet prescribed standards, making
them eligible for special grants-in--aid and technical assistance from the SHPO to assist
them in carrying out preservation activities at the local level. At least ten percent of
the annual Historic Preservation Fund grant made to States under the National Historic
Preservation Act must be distributed among Certified Local Governments.
Advisory Council on Historic Preservation: The Act creates the Advisory Council on
Historic Preservation, an independent Federal agency responsible for advising the
President and Congress on historic preservation matters, and reviewing and commenting
on agency actions that may affect historic properties (See "What is Section 106
Review?").
Federal Agency Responsibilities: The Act directs Federal agencies to name "Agency
Preservation Officers" to coordinate their historic preservation activities, to seek ways
to carry out their activities in accordance with the purposes of the Act, to identify
historic properties under their jurisdiction, to consider such properties when planning
actions might affect them, to give the Advisory Council an opportunity to comment on
such actions, and to document historic properties that cannot be preserved.
The National Historic Preservation Act and the programs it created are the major
components of the national historic preservation program.
For a free copy of the National Historic Preservation Act, write:
Publications Office
Advisory Council on Historic Preservation
1100 Pennsylvania Avenue, NW Suite 809
Washington, DC 20004
Prepared by Patricia L. Parker, National Park Service, May, 1987
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A service of the
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DISTRIBUTED BY INTERAGENCY RESOURCES DIVISION, WASHINGTON, D. C.
"HISTORIC PRESERVATION" and "HISTORIC PROPERTIES"
Local Preservation is a National Park Service publication series that provides technical
information concerning the national historic preservation program established by and
administered under the authority of the National Historic Preservation Act (See Local
Preservation "What is the National Historic Preservation Act?").
Two terms need to be defined for reference by readers of the Local Preservation Series,
because they are used in the Series in ways that, while consistent with the definitions in the
National Historic Preservation Act, could be misleading.
The Act defines historic property to mean "any prehistoric or historic district, site, building,
structure, or object included in, or eligible for inclusion in the National Register." Thus, when
we refer to "historic properties," we mean to include archeological sites and culturally
important places of significance in prehistory -- that is, sites and places used during the
thousands of years that American Indians occupied the continent before the coming of
Europeans -- as well as properties used during the "historic" period since the arrival of
Europeans.
The Act defines historic preservation to mean "identification, evaluation, recordation,
documentation, curation, acquisition, protection, management, rehabilitation, restoration,
stabilization, maintenance and reconstruction, or any combination of the foregoing activities."
Thus, when we refer to "historic preservation activities," we have a very wide range of
activities in mind. Some kinds of activities may not be possible under some circumstances,
however; for example, Congress has not recently permitted use of Historic Preservation Fund
monies for acquisition, management, rehabilitation, restoration, stabilization, maintenance, or
reconstruction of historic properties. "Historic preservation" as used in these papers refers to
whatever range of the above activities is permitted by the laws and regulations governing the
program under discussion.
Charitable Contributions
What is a certified rehabilitation? Taxpayers may deduct from their Federal income tax the value of historically important
land areas and certified historic structures donated to governments and other appropriate
A certified rehabilitation is a rehabilitation certified by NPS as being consistent with the recipients for historic preservation purposes. Donations of partial interests in such
historic character of the property and, where applicable, the district in which it is properties (e.g. easements) are also deductible.
located. NPS refers to the Secretary of the Interior's "Standards for Rehabilitation"
provided in Appendix 2, in certifying rehabilitations. The range of properties on which deductions can be claimed for donations is broader than
that on which the rehabilitation credit can be claimed. Archeological sites, rural historic
How is a building or rehabilitation certified? districts, and other land areas on or eligible for the National Register are included, as
are land areas within historic districts and lands adjacent to properties individually listed
NPS requires that owners complete a special form, the Historic Preservation in the Register where such areas contribute to the historical integrity of such
Certification Application (Form 10-168), for all certification requests. The form is properties. Properties do not have to be depreciable in order for the charitable
divided into three parts: Part 1 for evaluating the historic significance of a building; Part contribution deduction to be taken.
2 for describing rehabilitation work, and a third part requesting certification of
completed work. How does a taxpayer claim a charitable contribution deduction?
All applications are submitted to, and reviewed by, the State Historic Preservation The documentation needed to support a claim for a charitable contribution deduction
Officer (SHPO) before submission to NPS, which makes the final certification decision varies, depending on the property, the interests donated, and other factors. SHPO's and
after considering the SHPO's recommendations. NPS Regional Offices can provide assistance in developing the necessary documentation.
Part 1 evaluations need not be prepared for buildings already individually listed in the For further information, see:
National Register. A building within a district must be certified, based on review of a
Part 1 application, as contributing to the significance of that district. Part 1 "Preservation Tax Incentives for Historic Buildings." U.S. Department of the Interior,
applications are also used to gain preliminary determinations of significance for National Park Service (1990). Free brochure available from SHPO's and NPS Regional
individual buildings not yet listed in the Register; these determinations become final Offices.
when such buildings are actually listed.
Proposed rehabilitation is described on Part 2 of the application form. NPS issues a
preliminary approval of proposed work to projects that, as described, meet the Prepared by H. Ward Jandl and Patricia L. Parker, National Park Service, May, 1987
Secretary's Standards. The preliminary approval becomes final when the work is
completed and NPS can certify that the "Standards" have, in fact, been met. APPENDIX 1
Is there a fee for certification? The Secretary of the Interior's Standards for Evaluating Significance Within Registered
Historic Districts
NPS charges a fee for reviewing rehabilitation certification requests, based on the cost
of rehabilitation. 1. A building contributing to the historic significance of a district is one which by
location, design, setting, materials, workmanship, feeling, and association adds to
Where can application forms be obtained? the district's sense of time and place and historical development.
Historic Preservation Certification Application forms are available from SHPO's and 2. A building not contributing to the historical significance of a district is one which
from NPS Re gional Offices. does not add to the district's sense of time and place and historical development;
or one where the integrity of the location, design, setting, materials,
How is a State law or local ordinance, or a local historic district, certified? workmanship, feeling, and association has been so altered or has so deteriorated
that the overall integrity of the building has been irretrievably lost.
State and local governments that wish to have State laws, local ordinances, or local
historic districts not included in the National Register certified so that the rehabilitation 3. Ordinarily buildings that have been built within the past 50 years shall not be
of buildings contributing to such districts may qualify for the Federal historic considered to contribute to the significance of a district unless a strong
rehabilitation credit should contact their SHPO's for assistance in preparing and justification concerning their historical or architectural merit is given or the
submitting requests to NPS for such certification. historical attributes of the district are considered to be less than 50 years old.
A
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The Secretary of the Interior's Standards for Rehabilitation �! • ■__ n - _-_ _ ❑ -
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The Standards are to be applied to specific rehabilitation projects in a reasonable manner, .�� —m. � l , ,,,lail,,f 1 = i_
taking into consideration economic and technical feasibility.
• A service of the
1. A property shall be used for its historic purpose or be placed in a new use that requires
Ilieminimal change to the defining characteristics of the building and its site and I - - National Park Service
environment. DISTRIBUTED BY I N T E RAGE N C Y RESOURCES DIVISION, WASH I N G T O N, D. C.
2. The historic character of a property shall be retained and preserved. The removal of
historic materials or alteration of features and spaces that characterize a property shall
be avoided.
WHAT ARE
3. Each property shall be recognized as a physical record of its time, place, and use. THE HISTORIC PRESERVATION TAX INCENTIVES?
Changes that create a false sense of historical development, such as adding conjectural
features or architectural elements from other buildings, shall not be undertaken. Tax incentives for the preservation and rehabilitation of historic properties are among the most
useful tools a local government can use to protect and enhance its historical environment.
4. Most properties change over time; those changes that have acquired historic significance Some States and local governments provide reductions in property taxes and other State and
in their own right shall be retained and preserved. local taxes to encourage preservation of historic properties, and there are several Federal tax
incentives that apply to particular kinds of preservation activities for particular purposes. The
two most widely used Federal incentives, however, are the historic rehabilitation tax credit and
5. Distinctive features, finishes, and construction techniques or examples of craftsmanship the charitable contribution deduction.
that characterize a property shall be preserved.
Historic Rehabilitation Credit
6. Deteriorated historic features shall be repaired rather than replaced. Where the
severity of deterioration requires replacement of a distinctive feature, the new feature The Tax Reform Act of 1986 permits owners and some lessees of historic buildings to talc a
shall match the old in design, color, texture, and other visual qualities and, where 20% income tax credit on the cost of rehabilitating such buildings for industrial, commercial, or
possible, materials. Replacement of missing features shall be substantiated by rental residential purposes. The law also permits depreciation of such improvements over 27.5
documentary, physical, or pictorial evidence. years for a rental residential property and over 31.5 years for non-residential property. The
rehabilitated building must be a certified historic structure that is subject to depreciation, and
7. Chemical or physical treatments, such as sandblasting, that cause damage to historic the rehabilitation must be certified as meeting standards established by the National Park
materials shall not be used. The surface cleaning of structures, if appropriate, shall be Service (NPS).
undertaken using the gentlest means possible. What is a certified historic structure?
8. Significant archeological resources affected by a project shall be protected and A certified historic structure is:
preserved. If such resources must be disturbed, mitigation measures shall be
undertaken. * a structure individually listed in the National Register of Historic Places, or:
9. New additions,exterior alterations, or related new construction shall not destroy historic * a structure certified by NPS as contributing to a registered district. A
materials that characterize the property. The new work shall be differentiated from the registered district is one that is listed in the National Register, or designated
old and shall be compatible with the massing, size, scale, and architectural features to under a state or local statute which has been certified to contain criteria
which will substantially achieve the purpose of preserving and rehabilitating
protect the historic integrity of the property and its environment. _ buildings of significance to the district, and which is certified as substantially
meeting all of the requirements for listing of districts in the National
10. New additions and adjacent or related new construction shall be undertaken in such a Register.
manner that if removed in the future, the essential form and integrity of the historic
property and its environment would be unimpaired. The standards used in certifying structures within districts are given in Appendix 1.
Preservation Brief 8: Aluminum and Vinyl Siding on Historic Buildings: The Appropriate... Page 1 of 9
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Technical Preservation ServicesPreserva
"� s ,
fi�atlonal wank Service
u.s.Department of the interior
1"
Aluminum and Vinyl Siding
on Historic Buildings w.
The Appropriateness of Substitute { .., .
Materials for Resurfacing Historic bar
Wood Frame Buildings ". , •
� �
John H. Myers, revised by Gary L. Hume
»Historic Character of Buildings and Districts
»The Products and Their Installation
»Use of Aluminum or Vinyl Siding on Historic Buildings
»Summary_
»Reading List
A NOTE TO OUR USERS:The web versions of the Preservation Briefs differ somewhat from the printed versions.
Many illustrations are new, captions are simplified, illustrations are typically in color rather than black and white,and
some complex charts have been omitted.
A historic building is a product of the cultural heritage of its region, the
technology of its period, the skill of its builders, and the materials used for its
construction. To,assist owners, developers and managers of historic property in planning
and completing rehabilitation project work that will meet the Secretary's "Standards for
Rehabilitation"(36 CFR 67), the following planning process has been developed by the
National Park Service and is applicable to all historic buildings. This planning process is a
sequential approach to the preservation of historic wood frame buildings.
It begins with the premise that historic materials should
% , be retained wherever possible. When retention,
77 including retention with some repair, is not
'.it possible,then replacement of the irreparable historic
v , material can be considered. The purpose of this
a :. ::"A`,,` - ""r;""1: approach is to determine the appropriate level of
, : w* " ' treatment for the preservation of historic wood frame
buildings.
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Standard 6 of the Secretary of the Interior's Standards
ci4 7_~`�'� . for Rehabilitation states that "deteriorated architectural
- ,., features shall be repaired rather than replaced..Where
`' the severity of deterioration requires replacement of a
Historic wood siding exhibits rich '
and varied surface textures.They distinctive feature, the new feature shall match the old
range from hand-split clapboards in design, color, texture, and other visual qualities and,
of short lengths with feather- where possible, materials..." The Guidelines further
edged ends (shown here), to pit or
mill sawn boards which can be caution against "removing or radically changing wood
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beveled, rabbeted,or beaded. features which are important in defining the overall
Photo: NPS files. historic character of the building so that, as a result,
the character is diminished."
The planning process has the following four steps:
1. Identify and preserve those materials and features that are important in
defining the building's historic character. This may include features such as wood
siding, brackets, cornices, window architraves, doorway pediments, and their finishes
and colors.
2. Undertake routine maintenance on historic materials and features. Routine
maintenance generally involves the least amount of work needed to preserve the
materials and features of the building. For example, maintenance of a frame building
would include caulking and painting; or, where paint is extensively cracking and peeling,
its removal and the re-application of a protective paint coating.
3. Repair historic materials and features. For a historic material such as wood
siding, repair would generally involve patching and piecing-in with new material
according to recognized preservation methods.
4. Replace severely damaged or deteriorated historic materials and features in
kind. Replacing sound or repairable historic material is never recommended; however, if
the historic material cannot be repaired because of the extent of deterioration or
damage, then it will be necessary to replace an entire character-defining feature such as
the building's siding. The preferred treatment is always replacement in kind, that is, with
the same material. Because this approach is not always feasible, provision is made
under the recommended treatment options in the Guidelines that accompany the
Secretary of the Interior's Standards to consider the use of a compatible substitute
material. A substitute material should only be considered, however, if the form,
detailing, and overall appearance of the substitute material conveys the visual
appearance of the historic material, and the application of the substitute material does
not damage, destroy or obscure historic features.
In many cases, the replacement of wood siding on a historic building is proposed
because little attention has been given to the retention of historic materials. Instead, the
decision to use a substitute material is made because: (1) it is assumed that aluminum
or vinyl siding will be a maintenance-free material; and (2) there is the desire to give a
building a "remodeled" or "renovated" appearance. A decision to replace historic
material must, however, be carefully considered for its impact on the historic resource--
even when the model planning process has been followed and the appropriate treatment
is replacement.
Therefore, this brief focuses on the visual and physical consequences of using a
substitute material such as aluminum or vinyl siding for new siding installations on a
wood frame historic building. These concerns include the potential of damaging or
destroying historic material and features; the potential of obscuring historic material
and features; and, most important, the potential of diminishing the historic
character of the building.
The Historic Character of Buildings and Districts
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The character or "identity" of a historic building is established by its form, size, scale and
decorative features. It is also influenced by the choice of materials for the walls--by the
dimension, detailing, color, and other surface characteristics. This is particularly true for
wood frame buildings which are the typical objects of aluminum or vinyl siding
applications. Since wood has always been present in abundance in America, it has been
a dominant building material in most parts of the country. Early craftsmen used wood
for almost every aspect of building construction: for structural members such as posts,
beams and rafters, and for cladding materials and decorative details, such as trim,
shakes, and siding.
The variety of tools used, coupled with regional differences
in design and craftsmanship, has resulted in a richness and
`' = diversity of wood sidings in America. For example, narrow
boards with beveled, lapped joints called "clapboards" were
used on New England frame dwellings. The size and shape
of the "clapboards" were determined by the process of
;,. hand splitting or "riving" bolts of wood. The width, the
-�'` '' short lengths, the beveled lapping,- - g the "feathered"
horizontal joints, and the surface nailing of the clapboards
created a distinctive surface pattern that is recognizable as
an important part of the historic character of these
Aluminum and vinyl siding are structures.
available in a variety of widths
and colors, but the optional The sawn and hand-planed clapboards used throughout the
wood graining is not
characteristic of real wood Mid-Atlantic and Southern states in the eighteenth and
siding. Photo: NPS files. early nineteenth centuries, by contrast, have a wide
exposure--generally between six and eight inches. The
exposure of the siding, frequently coupled with a beaded edge, created a very different
play of light and shadow on the wall surface, thus resulting in a different character. The
"German" or "Novelty siding"--a milled siding that is thin above and thicker below with a
concave bevel--was used throughout many parts of the United States in the late
nineteenth and early twentieth century but with regional variations in material, profile,
and dimensions. One variation of this type of milled siding was called "California siding"
and was milled with a rabbetted or shiplap edge to insure a tight installation of the
weather boards. Shingles were also commonly used as an exterior cladding material,
and in buildings such as the Bungalow style houses, were often an important character-
defining feature of the exterior. Shingles were often applied in decorative patterns by
varying the lap, thus creating alternating rows of narrow exposures and wide exposures.
Shingles were also cut in geometric patterns such as diamond shapes and applied in
patterns. This treatment was commonly used in the gable end of shingled houses. Siding
and wood shingles were often used in combination with materials such as cobblestone
and brick in Bungalow style buildings to create a distinctive interplay of surfaces and
materials.
The primary concern, therefore, in considering ., ,, • � '
replacement siding on a historic building, is the * ¢
potential loss of those features such as the
beaded edge, "drop" profile, and the patterns
of application. Replacing historic wood siding
with new wood, or aluminum or vinyl siding1111 Ir
could severely diminish the unique aspects of
historic materials and craftsmanship. The
inappropriate use of substitute siding is When aluminum was installed on the house
especially dramatic where sufficient care is not on the right,the barge boards,scrollwork,
columns, and railings were removed.The
taken by the owner or applicator and the width distinctive shingled gable and attic vent were
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of the clapboards is altered, shadow reveals covered,further compromising the building's
are reduced, and molding or trim is changed or architectural integrity. Photo: NPS files.
removed at the corners, at cornices or around
windows and doors. Because substitute siding is usually added on top of existing siding,
details around windows and doors may appear set back from the siding rather than
slightly projecting; and if the relationship of molding or trim to the wall is changed, it
can result in the covering or removal of these historic features. New substitute siding
with embossed wood graining--intended to simulate the texture of wood--is also visually
inappropriate. Exaggerated graining would have been undesirable on real wood siding
and is generally found only after sandblasting, a destructive and totally unacceptable
treatment for wood.
While this discussion focuses primarily on the historic character of individual wood frame
buildings, of equal importance is the context of buildings that comprise a historic district
or neighborhood. Changes to the character-defining features of a building, such as
distinctive clapboarding and other wall surfaces and decorative trim, always have an
impact on more than just that building; they also alter the historic visual relationship
between the buildings in the district. If character-defining weatherboards, clapboards or
shingles are replaced on a number of buildings in a historic district, the historic character
of the entire district may be seriously damaged. Because of the potential impact some
substitute materials have on the character of a neighborhood or district, many
communities regulate their use through zoning ordinances and design review boards.
These ordinances and review boards usually require review and approval of proposed
alterations to a historic building that could potentially impact the historic character of
the building or the district, including the application of substitute materials, such as
aluminum or vinyl siding.
Preservation of a building or district and its historic character is based on the assumption
that the retention of historic materials and features and their craftsmanship are of
primary importance. Therefore, the underlying issue in any discussion of replacement
materials is whether or not the integrity of historic materials and craftsmanship has
been lost. Structures are historic because the materials and craftsmanship reflected in
their construction are tangible and irreplaceable evidence of our cultural heritage. To the
degree that substitute materials destroy and/or conceal the historic fabric, they will
always subtract from the basic integrity of historically and architecturally significant
buildings.
The Products and Their Installation
The use of aluminum and vinyl siding really involves two separate industries. The siding
materials themselves, including a variety of inside and outside corner pieces, trim and
molding pieces and panning for window and door frames, are produced by a
comparatively small number of manufacturers. The product information, advertising, and
any manufacturer's warranties on the product itself are handled by this part of the
industry. The installation of aluminum or vinyl siding is generally carried out by
independent contractors or applicators, who are frequently called "home improvement"
contractors, and they are not affiliated with the manufacturers. The manufacturer's
warranties normally do not cover the installation, or any damage or defect resulting
from the installation process.
Since the manufacturer has little control over the quality of the installation, both the
quality of the work and the sensitivity of the application are variable. This variation in
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.
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quality has traditionally been a problem in the industry and one which the industry and
its professional associations have attempted to correct through publishing and
disseminating information on the proper application of vinyl and aluminum siding.
' z -,--,,,-1 "_,
' '� ' Although it is sometimes argued that an artificial
, ;�x, H : , �;- ..,- siding application is reversible since it can be
1 ���:;= removed, there is frequently irreversible damage to
historic building materials if decorative features or
- r '. 5
i trim are permitted to be cut down or destroyed, or
E
g
. := removed by applicators and discarded. The
"1
. - installation process requires that the existing
ram` — A`• ` ' ,1 I: hi 1 R.,' ' surface be flat and free of "obstructions" so that
.•
the new siding will be smooth and even in
' a , Ai., -I 0appearance. To achieve the requisite flat surface,
• it 1 i� I s furring strips are usually placed over the wall
- ' surface (vertical furring strips for horizontal
,u "" , _�.� '� aluminum or vinyl siding and vice-versa for vertical
, iviNi IF siding). The potential danger in this type of surface
, w • ,ry_ preparation is that the furring strips may change
When a building is in need of the relationship between the plane of the wall and
maintenance, such as the house on the the projecting elements such as windows, door
right which needs painting,some trim, the cornice, or any other projecting trim or
owners consider installing aluminum or
vinyl siding.The result(see left) can be molding. Projecting details may also cause a
a complete loss of architectural problem. To retain them, additional cutting and
character due to the covering of details fitting will usually be required. Further, additional
and change of scale due to inappropriate
siding dimensions. Photo: NPS files. or special molding pieces, or "accessories" as they
are called by the industry, such as channels, inserts
and drip caps, will be needed to fit the siding around the architectural features. This
custom fitting of the siding will be more labor-intensive, adding to the cost of the siding
installation.
The existing wall fabric is further damaged by the nailing necessary to apply siding.
Either by nailing directly to the building fabric or by nailing the furring strips to the old
siding, the installation of aluminum or vinyl siding will leave numerous holes in wood
siding, molding, trim, window and door frames. When applied to brick or other masonry
units, the nail penetrations attaching the furring strips and siding can cause irreversible
cracking or spalling of the masonry. Although this reference to damaging masonry is
included as a point of fact, the application of aluminum or vinyl siding is highly
inappropriate to historic masonry buildings.
The Use of Aluminum or Vinyl Siding on Historic Buildings
The maintenance and periodic painting of wood frame structures is a time-consuming
effort and often a substantial expense for the homeowner. It is therefore understandable
that a product which promises relief from periodic painting and gives the building a new
exterior cladding would have considerable appeal. For these reasons, aluminum and
vinyl siding have been used extensively in upgrading and rehabilitating the nation's
stock of wood frame residential buildings. For historic residential buildings, aluminum or
vinyl siding may be an acceptable alternative only if (1) the existing siding is so
deteriorated or damaged that it cannot be repaired; (2) the substitute material can be
installed without irreversibly damaging or obscuring the architectural features and trim
of the building; and (3) the substitute material can match the historic material in size,
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Preservation Brief 8: Aluminum and Vinyl Siding on Historic Buildings: The Appropriate... Page 6 of 9
profile and finish so that there is no change in the character of the historic building. In
cases where a non-historic artificial siding has been applied to a building, the removal of
such a siding, and the application of aluminum or vinyl siding would, in most cases, be
an acceptable alternative, as long as the abovementioned first two conditions are met.
There are, however, also certain disadvantages in the use of a substitute material such
as aluminum or vinyl siding, and these factors should be carefully considered before a
decision is made to use such a material rather than the preferred replacement with new
wood siding duplicating the old.
Applying Siding without Dealing with Existing Problems
Since aluminum and vinyl sidings are typically marketed as home improvement items,
they are frequently applied to buildings in need of maintenance and repair. This can
result in concealing problems which are the early warning signs of deterioration. Minor
uncorrected problems can progress to the point where expensive, major repairs to the
structure become necessary.
If there is a hidden source of water entry within the wall or leakage from the roof, the
installation of any new siding will not solve problems of deterioration and rotting that are
occurring within the wall. If deferred maintenance has allowed water to enter the wall
through deteriorated gutters and downspouts, for example, the cosmetic surface
application of siding will not arrest these problems. In fact, if the gutters and
downspouts are not repaired, such problems may become exaggerated because water
may be channeled behind the siding. In addition to drastically reducing the efficiency of
most types of wall insulation, such excessive moisture levels within the wall can
contribute to problems with interior finishes such as paints or wallpaper, causing
peeling, blistering or staining of the finishes.
It cannot be overemphasized that a cosmetic treatment to hide difficulties such as
peeling paint, stains or other indications of deterioration is not a sound preservation
practice; it is no substitute for proper care and maintenance. Aluminum and vinyl siding
are not directly at fault in these situations since property owners should determine the
nature and source of their problems, then make appropriate repairs. The difficulty arises
when owners perceive the siding as the total solution to their required maintenance and
forgo other remedial action.
Durability and Cost
The questions of durability and relative costs of aluminum or vinyl siding compared to
the maintenance cost of historic materials are complex. It is important to consider these
questions carefully because both types of siding are marketed as long lasting, low
maintenance materials. Assuming that the substitute sidings are not damaged, and that
they will weather and age normally, there will be inevitable changes in color and gloss as
time passes. A normal application of aluminum or vinyl siding is likely to cost from two
to three times as much as a good paint job on wood siding. A sensitive application,
retaining existing trim, will cost more. Therefore, to break even on expense, the new
siding should last as long as two or three paintings before requiring maintenance. On
wood two coats of good quality paint on a properly prepared surface can last from 8 to
10 years, according to the U.S. Department of Agriculture. If a conservative life of seven
years is assumed for paint on wood, then aluminum and vinyl siding should last 15 to 21
years before requiring additional maintenance, to break even with the maintenance cost
for painting wood siding. Once painted, the aluminum and vinyl siding will require
repainting with the same frequency as wood.
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While aluminum siding can dent upon impact and the impact resistance of vinyl siding
decreases in low temperatures and, therefore, is susceptible to cracking from sharp
impact, these materials are generally not more vulnerable than wood siding and
shingles. All siding materials are subject to damage from storm, fire, and vandalism;
however, there is a major difference in the repairability of wood siding versus substitute
materials such as aluminum and vinyl. Although they can all be repaired, it is much
easier to repair wood siding and the repair, after painting, is generally imperceptible. In
addition, a major problem in the repairability of aluminum and vinyl siding, as
mentioned above, is matching color since the factory finishes change with time.
Matching the paint for wood siding has a greater likelihood of success.
Energy
Because of high fuel costs, there is a concern for energy conservation in historic
materials as well as in substitute materials. Because aluminum and vinyl siding can be
produced with an insulating backing, these products are sometimes marketed as
improving the thermal envelope of a historic building. The aluminum and vinyl material
themselves are not good insulators, and the thickness of any insulating backing would,
of necessity, be too small to add to the energy efficiency of a historic building. What
energy savings did accrue as a result of a siding application would probably be as much
the result of the creation of an air space between the old and new siding as the addition
of insulating material. If the historic wood siding were removed in the course of
installing the aluminum or vinyl siding (even with an insulating backing), the net result
would likely be a loss in overall thermal efficiency for the exterior sheathing.
Preservation Briefs Number 3, "Conserving Energy in Historic Buildings," notes that the
primary sources of energy loss in small frame buildings are the doors, windows and roof.
It is, therefore, more cost-effective to apply storm windows, weatherstripping and attic
insulation than to treat the sidewalls of these structures. There are numerous
publications on energy retrofitting which explain techniques of determining cost-
effectiveness based on utility costs, R-factors or materials and initial cost of the
treatment. Persons interested in this approach may wish to read "Retrofitting Existing
Houses for Energy Conservation: An Economic Analysis" published by the National
Bureau of Standards, or the U.S. Department of Housing and Urban Development
booklet "In the Bank or Up the Chimney." One such study in Providence, Rhode Island,
determined that for a two-story house, twenty-five feet square, the payback period for
twenty-three storm windows, two storm doors and six inches of attic insulation (R-20)
was 4.4 years while the payback period of aluminum siding with an R-factor of 2.5 was
29.96 years. Most of the information which is available supports the position that
aluminum or vinyl siding will not have a reasonable payback on an energy-saving basis
alone.
Summary
The intent of this brief has been to delineate issues that should be considered when
contemplating the use of aluminum or vinyl sidings on historic buildings and assessing
under what circumstances substitute materials such as artificial siding may be used
without damaging the integrity of the historic building or adversely changing its historic
character. Many property owners are faced with decisions weighing the historic value of
their building and its maintenance cost against the possible benefit of aluminum and
vinyl siding materials. To assist in making these decisions, "The Secretary of the
Interior's Standards for Rehabilitation and Guidelines for Rehabilitating Historic
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Preservation Brief 8: Aluminum and Vinyl Siding on Historic Buildings: The Appropriate... Page 8 of 9
Buildings" have been published and are available from National Park Service Regional
Offices and State Historic Preservation Offices. Further, since rehabilitation projects for
income-producing historic buildings often seek tax benefits under the 1981 Economic
Recovery Tax Act, as amended, it is essential that all work, such as the replacement of
exterior siding, be carried out in conformance with the Standards and be consistent with
the building's historic character to insure that the tax benefits are not denied.
...
As stated earlier, the application of aluminum and "��,� �'',►�`� - t '�A'
vinyl siding is frequently considered as an alternative .
to the maintenance of the original historic material. ."e%,;) j• '`
The implication is that the new material is an k, tw ,{;, � , t � �
economical and long-lasting alternative and thereforec '' f 4
somehow superior to the historic material. In reality, ( ; _ 1, rit,
historic building materials such as wood, brick and rill L stone, when properly maintained, are generally (
durable and serviceable materials. Their widespread +. 3 ' 'u*5
existence on tens of thousands of old buildings after ," A I-1
many decades in serviceable condition is proof that 9 �
r � �� 1.1
they are the original economic and long-lasting o . .. t
alternatives. All materials, including aluminum and Imr► � c. • r �
vinyl siding can fall into disrepair if abused or .. ., __ A��s►:.
neglected; however, the maintenance, repair and The inappropriate siding applied to
retention of historic materials are always the most the house on the right has altered the
character of the urban setting. Photo:
architecturally appropriate and usually the most NPS files.
economically sound measures when the objective is to
preserve the unique qualities of historic buildings.
The appropriate preservation decision on the use of a substitute material in the
rehabilitation of a historic building must always center on two principal concerns: the
possible damage or destruction of historic building materials; and, the possible negative
impact on the historic character of the building and the historic district or setting in
which the building is located. Because applications of substitute materials such as
aluminum and vinyl siding can either destroy or conceal historic building material and
features and, in consequence, result in the loss of a building's historic character, they
are not recommended by the National Park Service. Such destruction or concealment of
historic materials and features confuses the public perception of that which is truly
historic and that which is imitative.
Reading List
"Condensation Problems in Your House: Prevention and Solution." Information Bulletin
No. 373. Washington, D.C.: U.S. Department of Agriculture, 1974.
Kiefer, Matthew 3. "Vinyl and Aluminum Siding: Pro and Con." Report to the Ashmont Hill
Study Committee. Boston, Massachusetts: The Boston Landmarks Commission, 1977.
"Landmark and Historic District Commission." Vol. 4. No. 5. Washington, D.C.: National
Trust for Historic Preservation. October 1978.
"Moisture Conditions in Walls and Ceilings of a Simulated Older Home in Winter."
Madison, Wisconsin: Forest Products Laboratory USDA, 1977.
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Preservation Brief 8: Aluminum and Vinyl Siding on Historic Buildings: The Appropriate... Page 9 of 9
"Performance Criteria for Exterior Wall Systems." Washington, D.C.: National Bureau of
Standards, 1974.
"Rehab Right." Oakland, California: City of Oakland Planning Department, 1978.
Skoda, Leopold F. "Performance of Residential Siding Materials." Washington, D.C.:
National Bureau of Standards, 1972.
Wood Handbook: Wood as an Engineering Material. Washington, D.C.: Forest Products
Laboratory. U.S. Department of Agriculture, 1974.
Acknowledgements
•
This Preservation Brief was written by John H. Myers, Historical Architect,formerly with Technical Preservation
Services, and was published first in 1979.The Brief was substantially revised in 1984 by Gary L. Hume, Deputy
Division Chief, Preservation Assistance Division. H. Ward Jandl, Chief,Technical Preservation Services Branch,and
the following Branch staff members are to be thanked for reviewing the manuscript and making suggestions that
were incorporated into the final text: Emogene A. Bevitt, Kay Davidson Weeks,and Susan Dynes.
Washington, D.C.October, 1984.
Home page logo: Drawing: "A Tribute to Vinyl Siding. (Igloo)" reproduced from David Macaulay's Great
Moments in Architecture.Copyright 1978 by David Macaulay and reprinted permission of Houghton
Mifflin Company.
This publication has been prepared pursuant to the National Historic Preservation Act of
1966, as amended, which directs the Secretary of the Interior to develop and make
available information concerning historic properties. Technical Preservation Services
(TPS), Heritage Preservation Services Division, National Park Service prepares
standards, guidelines, and other educational materials on responsible historic
preservation treatments for a broad public.
Order Brief i Technical Preservation Services I Preservation Briefs l Search I questions/Answers
KDW
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Preservation Brief 9: The Repair of Historic Wooden Windows Page 1 of 11
Technical Preservation Services44,g Preservation Briefs
National Park Service
U.S.Department of the interior
The Repair of
Historic Wooden Windows
John H. Myers '
»Architectural or Historical Significance
»Physical Evaluation uj = ,
»Repair Class I: Routine Maintenance {
»Repair Class II: Stabilization •
»Repair Class III: Splices and Parts Replacement
»Weatherization
»Window Replacement
>>Conclusion
»Additional Reading.
A NOTE TO OUR USERS:The web versions of the Preservation Briefs differ somewhat from the printed versions.
Many illustrations are new, captions are simplified, illustrations are typically in color rather than black and white,and
some complex charts have been omitted.
The windows on many historic buildings are an important aspect of the
architectural character of those buildings. Their design, craftsmanship, or other
qualities may make them worthy of preservation. This is self-evident for ornamental
windows, but it can be equally true for warehouses or factories where the windows may
be the most dominant visual element of an otherwise plain building. Evaluating the
significance of these windows and planning for their repair or replacement can be a
complex process involving both objective and subjective considerations. The Secretary
of the Interior's Standards for Rehabilitation and the accompanying guidelines, call for
respecting the significance of original materials and features, repairing and retaining
them wherever possible, and when necessary, replacing them in kind. This Brief is based
on the issues of significance and repair which are implicit in the standards, but the
primary emphasis is on the technical issues of planning for the repair of windows
including evaluation of their physical condition, techniques of repair, and design
considerations when replacement is necessary.
Much of the technical section presents repair techniques as an instructional guide for the
do-it-yourselfer. The information will be useful, however, for the architect, contractor, or
developer on large-scale projects. It presents a methodology for approaching the
evaluation and repair of existing windows, and considerations for replacement, from
which the professional can develop alternatives and specify appropriate materials and
procedures.
Architectural or Historical Significance
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Preservation Brief 9: The Repair of Historic Wooden Windows Page 2 of 11
Evaluating the architectural or historical significance of windows is the first step in
planning for window treatments, and a general understanding of the function and history
of windows is vital to making a proper evaluation. As a part of this evaluation, one must
consider four basic window functions: admitting light to the interior spaces, providing
fresh air and ventilation to the interior, providing a visual link to the outside world, and
enhancing the appearance of a building. No single factor can be disregarded when
planning window treatments; for example, attempting to conserve energy by closing up
or reducing the size of window openings may result in the use of more energy by
increasing electric lighting loads and decreasing passive solar heat gains.
Historically, the first windows in early American
.i" houses were casement windows; that is, they
pi
, '; were hinged at the side and opened outward. In
°¢ the beginning of the eighteenth century single-
?� and double-hung windows were introduced.
41. t frir Subsequently many styles of these vertical
I� .� s l•d•Ing sash windows have come to be
Ott j rl 1;g! I<. f fi► associated with specific building periods or
, a -t ili' t '� .,`r-i architectural styles, and this is an important
BELF, � 0 consideration in determining the significance of
Littijk. k� windows, especially on a local or regional basis.
:.; . � Site-specific, regionally oriented architectural
rs comparisons should be made to determine the
• , + ` > significance of windows in question. Although
Windows are frequently important visual such comparisons may focus on specific window
focal points,especially on simple facades types and their details, the ultimate
such as this mill building. Replacement of determination of significance should be made
the multi-pane windows with larger panes
could dramatically alter the appearance of within the context of the whole building,
the building. Photo: NPS files. wherein the windows are one architectural
element.
After all of the factors have been evaluated, windows should be considered
significant to a building if they: 1) are original, 2) reflect the original design intent
for the building, 3) reflect period or regional styles or building practices, 4) reflect
changes to the building resulting from major periods or events, or 5) are examples of
exceptional craftsmanship or design. Once this evaluation of significance has been
completed, it is possible to proceed with planning appropriate treatments, beginning
with an investigation of the physical condition of the windows.
Physical Evaluation
The key to successful planning for window treatments is a careful evaluation of existing
physical conditions on a unit-by-unit basis. A graphic or photographic system may be
devised to record existing conditions and illustrate the scope of any necessary repairs.
Another effective tool is a window schedule which lists all of the parts of each window
unit. Spaces by each part allow notes on existing conditions and repair instructions.
When such a schedule is completed, it indicates the precise tasks to be performed in the
repair of each unit and becomes a part of the specifications. In any evaluation, one
should note at a minimum:
• 1) window location
• 2) condition of the paint
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Preservation Brief 9: The Repair of Historic Wooden Windows Page 3 of 11
• 3) condition of the frame and sill
• 4) condition of the sash (rails, stiles and muntins)
• 5) glazing problems
• 6) hardware, and
• 7) the overall condition of the window (excellent, fair, poor, and so forth)
Many factors such as poor design, moisture, vandalism, insect attack, and lack of
maintenance can contribute to window deterioration, but moisture is the primary
contributing factor in wooden window decay. All window units should be inspected to see
if water is entering around the edges of the frame and, if so, the joints or seams should
be caulked to eliminate this danger. The glazing putty should be checked for cracked,
loose, or missing sections which allow water to saturate the wood, especially at the
joints. The back putty on the interior side of the pane should also be inspected, because
it creates a seal which prevents condensation from running down into the joinery. The
sill should be examined to insure that it slopes downward away from the building and
allows water to drain off. In addition, it may be advisable to cut a dripline along the
underside of the sill. This almost invisible treatment will insure proper water runoff,
particularly if the bottom of the sill is flat. Any conditions, including poor original design,
which permit water to come in contact with the wood or to puddle on the sill must be
corrected as they contribute to deterioration of the window.
One clue to the location of areas of excessive .'.
moisture is the condition of the paint; therefore, i'
each window should be examined for areas of
paint failure. Since excessive moisture is
detrimental to the paint bond, areas of paint
blistering, cracking, flaking, and peeling usually
identify points of water penetration, moisture "01167"441
saturation, and potential deterioration. Failure of .;
•
the paint should not, however, be mistakenly � ���
interpreted as a sign that the wood is in poor t _ ^�, •
condition and hence, irreparable. Wood is f � k
frequently in sound physical condition beneath
Deterio t ' io ration' l
of poorly maintained windows
unsightly paint. After noting areas of paint usually begins on horizontal surfaces and at
failure, the next step is to inspect the condition joints,where water can collect and saturate
of the wood, particularly at the points identified the wood. Photo: NPS files.
during the paint examination.
Each window should be examined for operational soundness beginning with the lower
portions of the frame and sash. Exterior rainwater and interior condensation can flow
downward along the window, entering and collecting at points where the flow is blocked.
The sill, joints between the sill and jamb, corners of the bottom rails and muntin joints
are typical points where water collects and deterioration begins. The operation of the
window (continuous opening and closing over the years and seasonal temperature
changes) weakens the joints, causing movement and slight separation. This process
makes the joints more vulnerable to water which is readily absorbed into the endgrain of
the wood. If severe deterioration exists in these areas, it will usually be apparent on
visual inspection, but other less severely deteriorated areas of the wood may be tested
by two traditional methods using a small ice pick.
An ice pick or an awl may be used to test wood for soundness. The technique is simply
to jab the pick into a wetted wood surface at an angle and pry up a small section of the
wood. Sound wood will separate in long fibrous splinters, but decayed wood will lift up in
short irregular pieces due to the breakdown of fiber strength.
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Preservation Brief 9: The Repair of Historic Wooden Windows Page 4 of 11
Another method of testing for soundness consists of pushing a sharp object into the
wood, perpendicular to the surface. If deterioration has begun from the hidden side of a
member and the core is badly decayed, the visible surface may appear to be sound
wood. Pressure on the probe can force it through an apparently sound skin to penetrate
deeply into decayed wood. This technique is especially useful for checking sills where
visual access to the underside is restricted.
Following the inspection and analysis of the results, the scope of the necessary repairs
will be evident and a plan for the rehabilitation can be formulated. Generally the actions
necessary to return a window to "like new" condition will fall into three broad categories:
1) routine maintenance procedures, 2) structural stabilization, and 3) parts
replacement. These categories will be discussed in the following sections and will be
referred to respectively as Repair Class I, Repair Class II, and Repair Class III.
Each successive repair class represents an increasing level of difficulty, expense, and
work time. Note that most of the points mentioned in Repair Class I are routine
maintenance items and should be provided in a regular maintenance program for any
building. The neglect of these routine items can contribute to many common window
problems.
Before undertaking any of the repairs mentioned in the following sections all sources of
moisture penetration should be identified and eliminated, and all existing decay fungi
destroyed in order to arrest the deterioration process. Many commercially available
fungicides and wood preservatives are toxic, so it is extremely important to follow the
manufacturer's recommendations for application, and store all chemical materials away
from children and animals. After fungicidal and preservative treatment the windows may
be stabilized, retained, and restored with every expectation for a long service life.
Repair Class I: Routine Maintenance
Repairs to wooden windows are usually labor intensive and „--
relatively uncomplicated. On small scale projects this '•
'
allows the do-it-yourselfer to save money by repairing all p3
or part of the windows. On larger projects it presents the � f
opportunity for time and money which might otherwise be it i. , "' ,
spent on the removal and replacement of existing windows, 7
to be spent on repairs, subsequently saving all or part of
the material cost of new window units. Regardless of the '‘,-1
actual costs, or who performs the work, the evaluation t g
process described earlier will provide the knowledge fromWit-
which to specify an appropriate work program, establish vi ti •
the work element priorities, and identify the level of skill a' ' A
needed by the labor force.
This historic double-hung
The routine maintenance required window has many layers of
to upgrade a window to "like new" paint,some cracked and
condition normally includes the missing putty,slight separation
following steps: 1) some degree at the joints, broken sash
cords, and one cracked pane.
of interior and exterior paint Photo: NPS files.
removal, 2) removal and repair of
sash (including reglazing where necessary), 3) repairs to the
frame, 4) weatherstripping and reinstallation of the sash, and
5) repainting. These operations are illustrated for a typical
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Preservation Brief 9: The Repair of Historic Wooden Windows Page 5 of 11
I
A1 double-hung wooden window, but they may be adapted to
., i• other window types and styles as applicable.
4' k Historic windows have usually acquired many layers of paint
i, ime. Removal of excess layers
ing
`,,}r` , J i, paint twill facilitate operation of the windowr la restoredl flaking
t et , clarity of the original detailing. Some degree of paint removal is
,'` e4 also necessary as a first step in the proper surface preparation
for subsequent refinishing (if paint color analysis is desired, it
g;� should be conducted prior to the onset of the paint removal).
z • ,, There are several safe and effective techniques for removing
J - .4 i
,g y,:4. ,; paint from wood, depending on the amount of paint to be
,,) i I .,+1 .< removed.
After removing paint from . .
Paint removal should
the seam between the ,� 11:r•-,,\";441
interior stop and the begin on the interior ,y. f% '
jamb, the stop can be frames, being careful t 1
pried out and gradually , ' 1, � .
to remove the paint , •worked loose using a pair from the interior stopz74 ,
of putty knives as shown. o�(iw"ck rp,,
Photo: NPS files. and the parting bead, .4 ./.w
particularly along the x x #.
seam where these stops meet the jamb. This g., 4 t !4 �`
can be accomplished by running a utility knife « 19� o you
along the length of the seam, breaking the „
paint bond. It will then be much easier to Sash can be removed and repaired in a
remove the stop, the parting bead and the convenient work area. Paint is being removed
sash. The interior stop may be initially loosened from this sash with a hot air gun. Photo: NPS
from the sash side to avoid visible scarring of files.
the wood and then gradually pried loose using a pair of putty knives, working up and
down the stop in small increments. With the stop removed, the lower or interior sash
may be withdrawn. The sash cords should be detached from the sides of the sash and
their ends may be pinned with a nail or tied in a knot to prevent them from falling into
the weight pocket.
Removal of the upper sash on double-hung units is similar but the parting bead which
holds it in place is set into a groove in the center of the stile and is thinner and more
delicate than the interior stop. After removing any paint along the seam, the parting
bead should be carefully pried out and worked free in the same manner as the interior
stop. The upper sash can be removed in the same manner as the lower one and both
sash taken to a convenient work area (in order to remove the sash the interior stop and
parting bead need only be removed from one side of the window). Window openings can
be covered with polyethylene sheets or plywood sheathing while the sash are out for
repair.
The sash can be stripped of paint using appropriate techniques, but if any heat
treatment is used, the glass should be removed or protected from the sudden
temperature change which can cause breakage. An overlay of aluminum foil on gypsum
board or asbestos can protect the glass from such rapid temperature change. It is
important to protect the glass because it may be historic and often adds character to the
window. Deteriorated putty should be removed manually, taking care not to damage the
wood along the rabbet. If the glass is to be removed, the glazing points which hold the
glass in place can be extracted and the panes numbered and removed for cleaning and
reuse in the same openings. With the glass panes out, the remaining putty can be
removed and the sash can be sanded, patched, and primed with a preservative primer.
Hardened putty in the rabbets may be softened by heating with a soldering iron at the
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Preservation Brief 9: The Repair of Historic Wooden Windows Page 6 of 11
N
point of removal. Putty remaining on the glass may be softened by soaking the panes in
linseed oil, and then removed with less risk of breaking the glass. Before reinstalling the
glass, a bead of glazing compound or linseed oil putty should be laid around the rabbet
to cushion and seal the glass. Glazing compound should only be used on wood which has
been brushed with linseed oil and primed with an oil based primer or paint. The pane is
then pressed into place and the glazing points are pushed into the wood around the
perimeter of the pane.
The final glazing compound or putty is applied and beveled to complete the seal. The
sash can be refinished as desired on the inside and painted on the outside as soon as a
"skin" has formed on the putty, usually in 2 or 3 days. Exterior paint should cover the
beveled glazing compound or putty and lap over onto the glass slightly to complete a
weather-tight seal. After the proper curing times have elapsed for paint and putty, the
sash will be ready for reinstallation.
While the sash are out of the frame, the condition of the wood in the jamb and sill can
be evaluated. Repair and refinishing of the frame may proceed concurrently with repairs
to the sash, taking advantage of the curing times for the paints and putty used on the
sash. One of the most common work items is the replacement of the sash cords with
new rope cords or with chains. The weight pocket is frequently accessible through a door
on the face of the frame near the sill, but if no door exists, the trim on the interior face
may be removed for access. Sash weights may be increased for easier window operation
by elderly or handicapped persons. Additional repairs to the frame and sash may include
consolidation or replacement of deteriorated wood. Techniques for these repairs are
discussed in the following sections.
,' The operations just discussed summarize the efforts necessary to
:; ;.� , restore a window with minor deterioration to "like new" condition.
{ ry i< The techniques can be applied by an unskilled person with
'q 1 ,' minimal training and experience. To demonstrate the practicality
p.�•
. : of this approach, and photograph it, a Technical Preservation
Services staff member repaired a wooden double-hung, two over
'l 4 i= two window which had been in service over ninety years. The
;i' wood was structurally sound but the window had one broken
'••l r '' h pane, many layers of paint, broken sash cords and inadequate,
, i,t
t worn-out weatherstripping. The staff member found that the
{ frame could be stripped of paint and the sash removed quite
. , easily. Paint, putty, and glass removal required about one hour for
1 ° ` _, ° each sash, and the reglazing of both sash was accomplished in
Il .i;:, — ":"--4 I . about one hour. Weatherstripping of the sash and frame,
Following the replacement of the sash cords and reinstallation of the sash,
relatively simple parting bead, and stop required an hour and a half. These times
repairs,the window is refer onlyto individual operations; the entire process took several
weathertight, like new P r
in appearance,and days due to the drying and curing times for putty, primer, and
serviceable for many paint, however, work on other window units could have been in
years tole come.Photo: duringthese lagtimes.
NPS files. progress
Repair Class II: Stabilization
The preceding description of a window repair job focused on a unit which was
operationally sound. Many windows will show some additional degree of physical
deterioration, especially in the vulnerable areas mentioned earlier, but even badly
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Preservation Brief 9: The Repair of Historic Wooden Windows Page 7 of 11
r
damaged windows can be repaired using simple processes. Partially decayed wood can
be waterproofed, patched, built-up, or consolidated and then painted to achieve a sound
condition, good appearance, and greatly extended life. Three techniques for repairing
partially decayed or weathered wood are discussed in this section, and all three can be
accomplished using products available at most hardware stores.
One established technique for repairing wood which is split, checked or shows signs of
rot, is to: 1) dry the wood, 2) treat decayed areas with a fungicide, 3) waterproof with
two or three applications of boiled linseed oil (applications every 24 hours), 4) fill cracks
and holes with putty, and 5) after a "skin" forms on the putty, paint the surface. Care
should be taken with the use of fungicide which is toxic. Follow the manufacturers'
directions and use only on areas which will be painted. When using any technique of
building up or patching a flat surface, the finished surface should be sloped slightly to
carry water away from the window and not allow it to puddle. Caulking of the joints
between the sill and the jamb will help reduce further water penetration.
Y When sills or other members exhibit surface
,' weathering they may also be built-up using wood
putties or homemade mixtures such as sawdust
/ and resorcinol glue, or whiting and varnish. These
mixtures can be built up in successive layers, then
' _. sanded, primed, and painted. The same caution
-- about proper slope for flat surfaces applies to this
.. . technique.
I. Wood may also be strengthened and stabilized by
�`. '� ` �r�`'.: .. consolidation, using semirigid epoxies which
This illustrates a two-part expoxy saturate the porous decayed wood and then
patching compound used to fill the harden. The surface of the consolidated wood can
surface of a weathered sill and rebuild
the missing edge.When the epoxy then be filled with a semirigid epoxy patching
cures, it can be sanded smooth and compound, sanded and painted. Epoxy patching
painted to achieve a durable and compounds can be used to build up missing
waterproof repair. Photo: NPS files. sections or decayed ends of members. Profiles can
be duplicated using hand molds, which are created by pressing a ball of patching
compound over a sound section of the profile which has been rubbed with butcher's wax.
This can be a very efficient technique where there are many typical repairs to be done.
The process has been widely used and proven in marine applications; and proprietary
products are available at hardware and marine supply stores. Although epoxy materials
may be comparatively expensive, they hold the promise of being among the most
durable and long lasting materials available for wood repair. More information on
epoxies can be found in the publication "Epoxies for Wood Repairs in Historic Buildings,"
cited in the bibliography.
Any of the three techniques discussed can stabilize and restore the appearance of the
window unit. There are times, however, when the degree of deterioration is so advanced
that stabilization is impractical, and the only way to retain some of the original fabric is
to replace damaged parts.
Repair Class III: Splices and Parts Replacement
When parts of the frame or sash are so badly deteriorated that they cannot be stabilized
there are methods which permit the retention of some of the existing or original fabric.
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Preservation Brief 9: The Repair of Historic Wooden Windows Page 8 of 11
These methods involve replacing the deteriorated parts with new matching pieces, or
splicing new wood into existing members. The techniques require more skill and are
more expensive than any of the previously discussed alternatives. It is necessary to
remove the sash and/or the affected parts of the frame and have a carpenter or
woodworking mill reproduce the damaged or missing parts. Most millwork firms can
duplicate parts, such as muntins, bottom rails, or sills, which can then be incorporated
into the existing window, but it may be necessary to shop around because there are
several factors controlling the practicality of this approach. Some woodworking mills do
not like to repair old sash because nails or other foreign objects in the sash can damage
expensive knives (which cost far more than their profits on small repair jobs); others do
not have cutting knives to duplicate muntin profiles. Some firms prefer to concentrate
on larger jobs with more profit potential, and some may not have a craftsman who can
duplicate the parts. A little searching should locate a firm which will do the job, and at a
reasonable price. If such a firm does not exist locally, there are firms which undertake
this kind of repair and ship nationwide. It is possible, however, for the advanced do-it-
yourselfer or craftsman with a table saw to duplicate moulding profiles using techniques
discussed by Gordie Whittington in "Simplified Methods for Reproducing Wood
Mouldings," Bulletin of the Association for Preservation Technology, Vol. III, No. 4, 1971,
or illustrated more recently in The Old House, Time-Life Books, Alexandria, Virginia,
1979.
The repairs discussed in this section involve window frames which may be in very
deteriorated condition, possibly requiring removal; therefore, caution is in order. The
actual construction of wooden window frames and sash is not complicated. Pegged
mortise and tenon units can be disassembled easily, if the units are out of the building.
The installation or connection of some frames to the surrounding structure, especially
masonry walls, can complicate the work immeasurably, and may even require
dismantling of the wall. It may be useful, therefore, to take the following approach to
frame repair: 1) conduct regular maintenance of sound frames to achieve the longest
life possible, 2) make necessary repairs in place, wherever possible, using stabilization
and splicing techniques, and 3) if removal is necessary, thoroughly investigate the
structural detailing and seek appropriate professional consultation.
Another alternative may be considered if parts replacement is required, and that is sash
replacement. If extensive replacement of parts is necessary and the job becomes
prohibitively expensive it may be more practical to purchase new sash which can be
installed into the existing frames. Such sash are available as exact custom
reproductions, reasonable facsimiles (custom windows with similar profiles), and
contemporary wooden sash which are similar in appearance. There are companies which
still manufacture high quality wooden sash which would duplicate most historic sash. A
few calls to local building suppliers may provide a source of appropriate replacement
sash, but if not, check with local historical associations, the state historic preservation
office, or preservation related magazines and supply catalogs for information.
If a rehabilitation project has a large number of windows such as a commercial building
or an industrial complex, there may be less of a problem arriving at a solution. Once the
evaluation of the windows is completed and the scope of the work is known, there may
be a potential economy of scale. Woodworking mills may be interested in the work from
a large project; new sash in volume may be considerably less expensive per unit; crews
can be assembled and trained on site to perform all of the window repairs; and a few
extensive repairs can be absorbed (without undue burden) into the total budget for a
large number of sound windows. While it may be expensive for the average historic
home owner to pay seventy dollars or more for a mill to grind a custom knife to
duplicate four or five bad muntins, that cost becomes negligible on large commercial
projects which may have several hundred windows.
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Preservation Brief 9: The Repair of Historic Wooden Windows Page 9 of 11
Most windows should not require the extensive repairs discussed in this section. The
ones which do are usually in buildings which have been abandoned for long periods or
have totally lacked maintenance for years. It is necessary to thoroughly investigate the
alternatives for windows which do require extensive repairs to arrive at a solution which
retains historic significance and is also economically feasible. Even for projects requiring
repairs identified in this section, if the percentage of parts replacement per window is
low, or the number of windows requiring repair is small, repair can still be a cost
effective solution.
Weatherization
A window which is repaired should be made as energy efficient as possible by the use of
appropriate weatherstripping to reduce air infiltration. A wide variety of products are
available to assist in this task. Felt may be fastened to the top, bottom, and meeting
rails, but may have the disadvantage of absorbing and holding moisture, particularly at
the bottom rail. Rolled vinyl strips may also be tacked into place in appropriate locations
to reduce infiltration. Metal strips or new plastic spring strips may be used on the rails
and, if space permits, in the channels between the sash and jamb. Weatherstripping is a
historic treatment, but old weatherstripping (felt) is not likely to perform very
satisfactorily. Appropriate contemporary weatherstripping should be considered an
integral part of the repair process for windows. The use of sash locks installed on the
meeting rail will insure that the sash are kept tightly closed so that the weatherstripping
will function more effectively to reduce infiltration. Although such locks will not always
be historically accurate, they will usually be viewed as an acceptable contemporary
modification in the interest of improved thermal performance.
Many styles of storm windows are available to improve the thermal performance of
existing windows. The use of exterior storm windows should be investigated whenever
feasible because they are thermally efficient, cost-effective, reversible, and allow the
retention of original windows (see "Preservation Briefs: 3"). Storm window frames may
be made of wood, aluminum, vinyl, or plastic; however, the use of unfinished aluminum
storms should be avoided. The visual impact of storms may be minimized by selecting
colors which match existing trim color. Arched top storms are available for windows with
special shapes. Although interior storm windows appear to offer an attractive option for
achieving double glazing with minimal visual impact, the potential for damaging
condensation problems must be addressed. Moisture which becomes trapped between
the layers of glazing can condense on the colder, outer prime window, potentially
leading to deterioration. The correct approach to using interior storms is to create a seal
on the interior storm while allowing some ventilation around the prime window. In actual
practice, the creation of such a durable, airtight seal is difficult.
Window Replacement
Although the retention of original or existing windows is always desirable and this Brief
is intended to encourage that goal, there is a point when the condition of a window may
clearly indicate replacement. The decision process for selecting replacement windows
should not begin with a survey of contemporary window products which are available as
replacements, but should begin with a look at the windows which are being replaced.
Attempt to understand the contribution of the window(s) to the appearance of the
facade including: 1) the pattern of the openings and their size; 2) proportions of the
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Preservation Brief 9: The Repair of Historic Wooden Windows Page 10 of 11
frame and sash; 3) configuration of window panes; 4) muntin profiles; 5) type of wood;
6) paint color; 7) characteristics of the glass; and 8) associated details such as arched
tops, hoods, or other decorative elements. Develop an understanding of how the window
reflects the period, style, or regional characteristics of the building, or represents
technological development.
Armed with an awareness of the significance of the existing window, begin to search for
a replacement which retains as much of the character of the historic window as possible.
There are many sources of suitable new windows. Continue looking until an acceptable
replacement can be found. Check building supply firms, local woodworking mills,
carpenters, preservation oriented magazines, or catalogs or suppliers of old building
materials, for product information. Local historical associations and state historic
preservation offices may be good sources of information on products which have been
used successfully in preservation projects.
Consider energy efficiency as one of the factors for replacements, but do not let it
dominate the issue. Energy conservation is no excuse for the wholesale destruction of
historic windows which can be made thermally efficient by historically and aesthetically
acceptable means. In fact, a historic wooden window with a high quality storm window
added should thermally outperform a new double-glazed metal window which does not
have thermal breaks (insulation between the inner and outer frames intended to break
the path of heat flow). This occurs because the wood has far better insulating value than
the metal, and in addition many historic windows have high ratios of wood to glass, thus
reducing the area of highest heat transfer. One measure of heat transfer is the U-value,
the number of Btu's per hour transferred through a square foot of material. When
comparing thermal performance, the lower the U-value the better the performance.
According to ASHRAE 1977 Fundamentals, the U-values for single glazed wooden
windows range from 0.88 to 0.99. The addition of a storm window should reduce these
figures to a range of 0.44 to 0.49. A non-thermal break, double-glazed metal window
has a U-value of about 0.6.
Conclusion
Technical Preservation Services recommends the retention and repair of original
windows whenever possible. We believe that the repair and weatherization of existing
wooden windows is more practical than most people realize, and that many windows are
unfortunately replaced because of a lack of awareness of techniques for evaluation,
repair, and weatherization. Wooden windows which are repaired and properly
maintained will have greatly extended service lives while contributing to the historic
character of the building. Thus, an important element of a building's significance will
have been preserved for the future.
Additional Reading
ASHRAE Handbook 1977 Fundamentals. New York: American Society of Heating,
Refrigerating and Air-conditioning Engineers, 1978 (chapter 26).
Ferro, Maximillian. Preservation: Present Pathway to Fall River's Future. Fall River,
Massachusetts: City of Fall River, 1979 (chapter 7).
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Preservation Brief 9: The Repair of Historic Wooden Windows Page 11 of 11
"Fixing Double-hung Windows." Old House Journal (no. 12, 1979): 135.
Morrison, Hugh. Early American Architecture. New York: Oxford University Press, 1952.
Phillips, Morgan, and Selwyn, Judith. Epoxies for Wood Repairs in Historic Buildings.
Washington, DC: Technical Preservation Services, U.S. Department of the Interior
(Government Printing Office, Stock No. 024016000951), 1978.
Rehab Right. Oakland, California: City of Oakland Planning Department, 1978 (pp.
7883).
"Sealing Leaky Windows." Old House Journal (no. 1, 1973): 5.
Smith, Baird M. "Preservation Briefs: 3 Conserving Energy in Historic Buildings."
Washington, DC: Technical Preservation Services, U.S. Department of the Interior,
1978.
Weeks, Kay D. and David W. Look, "Preservation Briefs: 10 Exterior Paint Problems on
Historic Woodwork." Washington, DC: Technical Preservation Services, U.S. Department
of the Interior, 1982.
Washington, D.C. 1981
Home page logo: Historic six-over-six windows--preserved. Photo: NPS files.
This publication has been prepared pursuant to the National Historic Preservation Act of
1966, as amended, which directs the Secretary of the Interior to develop and make
available information concerning historic properties. Technical Preservation Services
(TPS), Heritage Preservation Services Division, National Park Service prepares
standards, guidelines, and other educational materials on responsible historic
preservation treatments for a broad public.
Order Brief l Technical Preservation Services l Preservation Briefs I Search I Questions/Answers
KDW
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1'
Preservation Brief 14: New Exterior Additions to Historic Buildings: Preservation Concer... Page 1 of 9
Technical Preservation Services 7
Preservation Briefs National Park Service :
U.S.Department of the interior 'i'
New Exterior Additions
to Historic Buildings {r �
Preservation Concerns
KayD. Weeks `t� . ,,� '�
Z Hf Y
»Preserving Significant Historic Materials and Features
»Preserving the Historic Character
»Protecting the Historical Significance ••�..: - ».
»Conclusion .44
>Additional Reading
A NOTE TO OUR USERS:The web versions of the Preservation Briefs differ somewhat from the printed versions.
Many illustrations are new, captions are simplified, illustrations are typically in color rather than black and white, and
some complex charts have been omitted.
Because a new exterior addition to a historic building can damage or destroy significant
materials and can change the building's character, an addition should be considered only
after it has been determined that the new use cannot be met by altering nonsignificant,
or secondary, interior spaces. If the new use cannot be met in this way, then an
attached addition may be an acceptable alternative if carefully planned. A new addition
should be constructed in a manner that preserves significant materials and features and
preserves the historic character. Finally, an addition should be differentiated from the
historic building so that the new work is not confused with what is genuinely part of the
past.
Change is as inevitable in buildings and neighborhoods as it is in individuals
and families. Never static, buildings and neighborhoods grow, diminish, and continue
to evolve as each era's technological advances bring conveniences such as heating,
street paving, electricity, and air conditioning; as the effects of violent weather,
uncontrolled fire, or slow unchecked deterioration destroy vulnerable material, as
businesses expand, change hands, become obsolete, as building codes are established
to enhance life safety and health; or as additional family living space is alternately
needed and abandoned.
Preservationists generally agree that the history of a building,
together with its site and setting, includes not only the period of
original construction but frequently later alterations and additions.
While each change to a building or neighborhood is undeniably
part of its history--much like events in human life--not every
change is equally important. For example, when a later, clearly
nonsignificant addition is removed to reveal the original form,
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Preservation Brief 14: New Exterior Additions to Historic Buildings: Preservation Concer... Page 2 of 9
materials, and craftsmanship, there is little complaint about a loss
to history. I
When the subject of new exterior additions is introduced, however,
areas of agreement usually tend to diminish. This is
understandable because the subject raises some serious questions.
Can a historic building be enlarged for a new use without
destroying what is historically significant? And just what is 4 • .—
significant about each particular historic building that should be Pt,
preserved? Finally, what new construction is appropriate to the old t5 %'` � "1111h
building?
The vast amount of literature on the subject of change to 1, �,. mt
America's built environment reflects widespread interest as well as
divergence of opinion. New additions have been discussed by w,
historians within a social and political, framework; by architectural
historians in terms of construction technology and style; and bye_ - ,
urban planners as successful or unsuccessful contextual design.
Within the historic preservation programs of the National Park The historic character
of this commercial
Service, however, the focus has been and will continue to be the building has been
protection of those resources identified as worthy of listing in the radically changed by a
National Register of Historic Places. replicative four-story
addition.This
approach does not
National Register Listing-- meet the Standards for
Rehabilitation. Photo:
Acknowledging Change While Protecting NPS files.
Historical Significance
Entire districts or neighborhoods may be listed in the National Register of Historic Places
for their significance to a certain period of American history (e.g., activities in a
commercial district between 1870 and 1910). This "framing" of historic districts has led
to a concern that listing in the National Register may discourage any physical change
beyond a certain historical period--particularly in the form of attached exterior additions.
This is not the case. National Register listing does not mean that an entire building or
district is frozen in time and that no change can be made without compromising the
historical significance. It also does not mean that each portion of a historic building is
equally significant and must be retained intact and without change. Admittedly, whether
an attached new addition is small or large, there will always be some loss of material
and some change in the form of the historic building. There will also generally be some
change in the relationship between the buildings and its site, neighborhood or district.
Some change is thus anticipated within each rehabilitation of a building for a
contemporary use.
Scope of National Park Service Interest in New Exterior Additions
The National Park Service interest in new additions is simply this--a new addition to a
historic building has the potential to damage and destroy significant historic material and
features and to change its historic character. A new addition also has the potential to
change how one perceives what is genuinely historic and thus to diminish those qualities
that make the building eligible for listing in the National Register of Historic Places. Once
these basic preservation issues have been addressed, all other aspects of designing and
constructing a new addition to extend the useful life of the historic building rest with the
creative skills of the architect.
The intent of this Brief, then, is to provide guidance to owners and developers planning
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Preservation Brief 14: New Exterior Additions to Historic Buildings: Preservation Concer... Page 3 of 9
t
additions to their historic buildings. A project involving a new addition to a historic
building is considered acceptable within the framework of the National Park Service's
standards if it:
1. Preserves significant historic materials and features; and
2. Preserves the historic character; and
3. Protects the historical significance by making a visual distinction between
old and new.
Paralleling these key points, the Brief is organized into three sections. Case study
examples are provided to point out acceptable and unacceptable preservation
approaches where new use requirements were met through construction of an exterior
addition. These examples are included to suggest ways that change to historic buildings
can be sensitively accomplished, not to provide in-depth project analyses, endorse or
critique particular architectural design, or offer cost and construction data.
1. Preserving Significant Historic Materials and Features
Connecting a new exterior addition always involves some degree of material loss to an
external wall of a historic building and, although this is to be expected, it can be
minimized. On the other hand, damage or destruction of significant materials and
craftsmanship such as pressed brick, decorative marble, cast stone, terra-cotta, or
architectural metal should be avoided, when possible.
Generally speaking, preservation of historic buildings is enhanced by avoiding all but
minor changes to primary or "public" elevations. Historically, features that distinguish
one building or a row of buildings and can be seen from the streets or sidewalks are
most likely to be the significant ones. This can include window patterns, window hoods,
or shutters; porticoes, entrances, and doorways; roof shapes, cornices, and decorative
moldings; or commercial storefronts with their special detailing, signs, and glazing.
Beyond a single building, entire blocks of urban or residential structures are often closely
related architecturally by their materials, detailing, form, and alignment. Because
significant materials and features should be preserved, not damaged or hidden, the first
place to consider constructing a new addition is where such material loss will be
minimized. This will frequently be on a secondary side or rear elevation. For both
economic and social reasons, secondary elevations were often constructed of "common"
material and were less architecturally ornate or detailed.
In constructing the new addition, one way to
. `ti �� minimize overall material loss is simply to
--- - `,, �~� reduce the size of the new addition in
r �k , ---. --1n,,.., relationship to the historic building. If a new
i- 1 ,5` addition will abut the historic building along one
4;1 i. .: - — i �1 elevation or wrap around a side and rear
r
" ` �` q ` ielevi_1".: 1 , i j interiors may result in a high degree of loss--
' `. ...•- � : � o --. exterior walls as well as significant interior
----:�-.- spaces and features. Another way to minimize
Two historic commercial buildings were loss is to limit the size and number of openings
successfully joined as part of a larger between old and new.
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Preservation Brief 14: New Exterior Additions to Historic Buildings: Preservation Concer... Page 4 of 9
1
rehabilitation project.The glass connector A particularly
detail is shown below. Photo: Martha L. successful ,!
Werenfels, AIA. ,L .. +....,:, n,•
method to di
reduce damage gg 7: _ . ..
is to link the new addition to the historic block by means z-Bui '"-
of a hyphen or connector. In this way, only the ` 1,.
connecting passageway penetrates a historic side wall; -,.-7 � -4
the new addition can be visually and functionally related yyGG `"`M t.""
while historic materials remain essentially intact and r -
historic exteriors remain uncovered.
NOR z ,
1IMII _._
Although a general recommendation is to construct a x. -- ,= 1 I
new addition on a secondary elevation, there are several ' i I _
.,..;.-
exceptions. First there maysimply be no secondary3
P Y . A. -. Y x.;' .
elevation--some important freestanding buildings have _.�+,. - ,. f t
significant materials and features on all sides . making = MMli,. t
any above-ground addition too destructive to be _ ; __ ,
considered. Second, a structure or group of structures This small glass connector between
together with their setting (for example, in a National two historic buildings is
Historic Park) may be of such significance in American appropriately set back.This
historythat anynew addition would not onlydamage approach meets the Standards for
g Rehabilitation. Photo: Martha L.
materials and alter the buildings' relationship to each Werenfels,AIA.
other and the setting, but seriously diminish the public's
ability to appreciate a historic event or place. Finally, there are other cases where an
existing side or rear elevation was historically intended to be highly visible, is of special
cultural importance to the neighborhood, or possesses associative historical value. Then,
too, a secondary elevation should be treated as if it were a primary elevation and a new
addition should be avoided.
2. Preserving the Historic Character
The second, equally important, consideration is
, '- whether or not the new addition will preserve the
resource's historic character. The historic
' "� character of each building may differ, but a
0 3
methodology of establishing it remains the same.
,, „,„„, ..„,„„, , ,
,,- ,„.... .,,,,_ , Knowing the uses and functions a building has
E g i7.7,: .,4,,,.,, ,,,2 1,.., ,,e..,,,. i served over time will assist in making what is
+ essentially a physical evaluation. But while written
,, . t ,.t4 , 'it ill' and pictorial documentation can provide a
r,,F x r i'l framework for establishing the building's history
i' `� e ,, ,.z the historic character, to a large extent, is '
'� '1 embodied in the physical aspects of the historic
,�► .u. .1°_ , ;: ,}.�, building itself--its shape, its materials, its
_ — �w; „.. � features, its craftsmanship, its window
arrangements, its colors, its setting, and its
This new stair tower addition on the rear interiors. It is onlyafter the historic character has
elevation of a historic townhouse is
compatible in size,scale,and materials. been correctly identified that reasonable decisions
This approach meets the Standards for about the extent--or limitations--of change can be
Rehabilitation. Photo: NPS files. made.
To meet National Park Service preservation standards, a new addition must be
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Preservation Brief 14: New Exterior Additions to Historic Buildings: Preservation Concer... Page 5 of 9
f
"compatible with the size, scale, color, material, and character" of the building to which
it is attached or its particular neighborhood or district. A new addition will always change
the size or actual bulk of the historic building. But an addition that bears no relationship
to the proportions and massing of the historic building--in other words, one that
overpowers the historic form and changes the scale will usually compromise the historic
character as well.
t.; The appropriate size for a new addition varies from
building to building; it could never be stated in a
} --- ,,, tidy square or cubic footage ratio, but the historic
t., '~ � . building's existing proportions, site, and setting can
helpset somegeneralparameters for enlargement.
.4 ,, . .. 9
r To some extent, there is a predictable relationship
between the size of the historic resource and the
‘i • degree of change a new addition will impose.
ii
` ,� ``" For example, in the case of relatively low buildings
1 g `",:' i (small-scale residential or commercial structures) it
-- is difficult, if not impossible, to minimize the impact
' of adding an entire new floor even if the new
This new stairtower addition on a addition is set back from the plane of the facade.
historic university building has been
constructed on a highly visible side Alteration of the historic proportions and profile will
elevation.Together with its contrasting likely change the building's character. On the other
color and size,it obscures the historic hand, a rooftop addition to an eight story building in
form and roofline.This approach does
not meet the Standards for a historic district of other tall buildings might not
Rehabilitation. Photo: Martha L. affect the historic character simply because the new
Werenfels,AIA. work would not be visible from major streets. A
number of methods have been used to help predict
the effect of a proposed rooftop addition on the historic building and district, including
pedestrian sight lines, three-dimensional schematics and computer-assisted design
(CAD). Sometimes a rough full-size mock up of a section or bay of the proposed addition
can be constructed using temporary material; the mockup can then be photographed
and evaluated from critical vantage points.
„,,,,,,,,-,7,,,,,,,,-), :.:- ,,, ,
In the case of freestanding residential
structures, the preservation considerations ., i, 11;`f
are generally twofold. First, a large f '' r ;';; ...
addition built out on a highly visible �. }' �
elevation can radically alter the historic ' '' t, 4
form or obscure features such as a - 1, , �� , 2
decorative cornice or window ` , ,. :
ornamentation. Second, an addition that ''? (�
fills in a planned void on a highly visible 1l �' t . "f _
elevation (such as a "U" shaped plan or
feature such as a porch) may also alter the _= .•,... .. _. .,• — .9
historic form and, as a result, change the A sizeable addition was placed on a non-significant
historic character. rear elevation of a late-19th century Greek Revival
house that was rehabilitated for use as a bank
with a drive-up component.The old building and
Some historic structures such as new addition were sensitively joined by a small
connecting hyphen.This approach meets the
government buildings, metropolitan Standards for Rehabilitation.Photo: NPS files.
museums, or libraries may be so massive
in size that a large-scale addition may not compromise the historic character. Yet similar
expansion of smaller buildings would be dramatically out of scale. In summary, where
any new addition is proposed, correctly assessing the relationship between actual size
and relative scale will be a key to preserving the character of the historic building.
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Constructing the new addition on a
71 secondary side or rear elevation--in addition
i.
to material preservation--will also address
' preservation of the historic character.
,,s Primarily, such placement will help to
> ' preserve the building's historic form and
�� relationship to its site and setting. Historic
, � � �, landscape features, including distinctive
t4sir ` �� �_ � � grade variations, need to be respected; and
;; , '_ , x� _ any new landscape features such as plants
=} .- '"�`' 6 ` fix. and trees kept at a scale and density that
""a .. - r "�'��'` would not interfere with appreciation of the
,,, :,. _. «ter `'.,
A contemporary new addition (above left)was historic resource Itself.
designed to fit into a nonsignificant U-shaped
area on a rear elevation of a historic library In highly developed urban areas, locating a
building. Note the new addition is lower than the
historic building and clearly differentiated in new addition on a less visible side or rear
appearance.This approach meets the Standards elevation may be impossible simply because
for Rehabilitation. Photo: NPS files. there is no available space. In this instance,
there may be alternative ways to help
preserve the historic character. If a new addition is being connected to the adjacent
historic building on a primary elevation, the addition may be set back from the front wall
plane so the outer edges defining the historic form are still apparent. In still other cases,
some variation in material, detailing, and color may provide the degree of differentiation
necessary to avoid changing the essential proportions and character of the historic
building.
3. Protecting the Historical Significance
Making a Visual Distinction Between Old and New
The following statement of approach could be applied equally to the preservation of
districts, sites, buildings, structures, and objects of National Register significance: "A
conservator works within a conservation ethic so that the integrity of the object as an
historic entity is maintained. The concern is not just with the original state of the object,
but the way in which it has been changed and used over the centuries. Where a new
intervention must be made to save the object, either to stabilize it or to consolidate it, it
is generally accepted that those interventions must be clear, obvious, and reversible. It
is this same attitude to change that is relevant to conservation policies and attitudes to
historic towns..." (1)
` ._ ' Rather than establishing a clear and obvious
- difference between old and new, it mightk - seem more in keeping with the historic
""ft r"""r"r"Pi"rrrttrrr"rrrr'�rttt�•rrrr.`S character simply to repeat the historic form,
t
_ material, features, and detailing in a new
�° addition. But when the new work is
F t' `� indistin uishable from the old in a g ppearance
,' ; = .. i then the "real" National Register property may
t zzeN !t '' ,- . of no longer be perceived and appreciated by the
This highly visible new rooftop addition public.
appears to be part of the historic building
because of its replicative design and
historicized detailing, such as the arched Thus, the third consideration in planning a
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V
windows.This approach does not meet the new addition is to be sure that it will protect
Standards for Rehabilitation. Photo: NPS files. those visual qualities that made the building
eligible for listing in the National Register of
Historic Places.
A question often asked is what if the historic character is not compromised by an
addition that appears to have been built in the same period? A small porch or a wing
that copied the historic materials and detailing placed on a rear elevation might not alter
the public perception of the historic form and massing. Therefore, it is conceivable that a
modest addition could be replicative without changing the resource's historic character;
generally, however, this approach is not recommended because using the same wall
plane, roof line, cornice height, materials, siding lap, and window type in an addition can
easily make the new work appear to be part of the historic building. If this happens on a
visible elevation, it becomes unclear as to which features are historic and which are new,
thus confusing the authenticity of the historic resource itself.
The National Park Service policy on new additions, adopted in 1967, is an outgrowth and
continuation of a general philosophical approach to change first expressed by John
Ruskin in England in the 1850s, formalized by William Morris in the founding of the
Society for the Protection of Ancient Buildings in 1877, expanded by the Society in 1924
and, finally, reiterated in the 1964 Venice Charter--a document that continues to be
followed by 64 national committees of the International Council on Monuments and Sites
(ICOMOS). The 1967 Administrative Policies for Historical Areas of the National Park
System thus states, "...a modern addition should be readily distinguishable from the
older work; however, the new work should be harmonious with the old in scale,
proportion, materials, and color. Such additions should be as inconspicuous as possible
from the public view." Similarly, the Secretary of the Interior's 1977 "Standards for
Rehabilitation" call for the new work to be "compatible with the size, scale, color,
material, and character of the property, neighborhood, or environment."
Conclusion
A major goal of our technical assistance program is a heightened awareness of
significant materials and the historic character prior to construction of a new exterior
addition so that essential change may be effected within a responsible preservation
context. In summary, then, these are the three important preservation questions to ask
when planning a new exterior addition to a historic resource:
1. Does the proposed addition preserve significant historic materials and
features?
2. Does the proposed addition preserve the historic character?
3. Does the proposed addition protect the historical significance by making a
visual distinction between old and new?
If the answer is YES to all three questions, then the new addition will protect significant
historic materials and the historic character and, in doing so, will have satisfactorily
addressed those concerns generally held to be fundamental to historic preservation.
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New Exterior Additions to Historic Buildings
Preserve Significant Historic Materials and Features.
Avoid constructing an addition on a primary or other character- defining elevation to
ensure preservation of significant materials and features.
Minimize loss of historic material comprising external walls and internal partitions and
floor plans.
Preserve the Historic Character
Make the size, scale, massing, and proportions of the new addition compatible with the
historic building to ensure that the historic form is not expanded or changed to an
unacceptable degree.
Place the new addition on an inconspicuous side or rear elevation so that the new work
does not result in a radical change to the form and character of the historic building.
Consider setting an infill addition or connector back from the historic buildings wall plane
so that the form of the historic building--or buildings--can be distinguished from the new
work.
Set an additional story well back from the roof edge to ensure that the historic building's
proportions and profile are not radically changed.
Protect the Historical Significance--Make a Visual Distinction
Between Old and New
Plan the new addition in a manner that provides some differentiation in material, color,
and detailing so that the new work does not appear to be part of the historic building.
The character of the historic resource should be identifiable after the addition is
constructed.
Additional Reading
Architecture: The AIA Journal, "Old and New," November, 1983.
Brolin, Brent C. Architecture in Context: Fitting New Buildings with Old. New York: Van
Nostrand Reinhold, 1980.
Good Neighbors: Building Next to History. State Historical Society of Colorado, 1980.
International Council on Monuments and Sites (ICOMOS). International Charter for the
Conservation and Restoration of Monuments and Sites (Venice Charter), 1966.
National Trust for Historic Preservation. Old and New Architecture: Design Relationship.
Washington, D.C.: Preservation Press. 1980.
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Preservation Brief 14: New Exterior Additions to Historic Buildings: Preservation Concer... Page 9 of 9
Rehab Right: How to Rehabilitate Your Oakland House Without Sacrificing Architectural
Assets. City of Oakland Planning Department. Oakland, California, 1978.
Ruskin, John. The Seven Lamps of Architecture. London: George Allen and Unwin, Ltd.,
1925.
Schmertz, Mildred F., and Architectural Record Editors. New Life for Old Buildings. New
York: Architectural Record Books, McGraw-Hill, 1980.
The Secretary of the Interior's Standards for Rehabilitation and Guidelines for
Rehabilitating Historic Buildings. Washington, D.C.: Preservation Assistance Division.
National Park Service, U.S. Department of the Interior, rev. 1983.
(1) Note: Roy Worskett, RIBA, MRTIP, "Improvement of Urban Design in Europe and the
United States: New Buildings in Old Settings." Background Report (prepared July, 1984)
for Seminar at Strasbourg, France, October, 1984.
Acknowledgements
First special thanks go to Ernest A. Connally, Gary L. Hume, and W. Brown Morton,III for their efforts in establishing
and refining our preservation and rehabilitation standards over the past 20 years. ("The Secretary of the Interior's for
Historic Preservation Projects (now"The Secretary of the Interior's Standards for the Treatment of Historic Properties
(Rev. 1995)"constitute the policy framework of this,and every technical publication developed in the Preservation
Assistance Division.) H. Ward Jandl, Chief,Technical Preservation Services Branch, is credited with overall
supervision of the project. Next appreciation is extended to the Branch professional staff,the NPS cultural programs
regional offices, the Park Historic Architecture Division, and the National Conference of State Historic Preservation
Officers for their thoughtful comments. Finally,the following specialists in the field are thanked for their time in
reviewing and commenting on the manuscript: Bruce Judd,AIA, Nore V. Winter,John Cullinane,AIA, Ellen Beasley,
Vicki Jo Sandstead,Judith Kitchen,Andrea Nadel, Martha L. Werenfels, Diane Pierce, Colden Florance, FAIA, and H.
Grant Dehart,AIA.The photograph of Chicago's Newberry Library with the Harry Weese and Associates' 1981
addition was graciously lent to us by David F. Dibner, FAIA, and Amy Dibner-Dunlap, co-authors of Buildings
Additions Design, McGraw-Hill, 1985.
Washington, D.C. September, 1986.
Home page logo:Approriate new stair tower addition. Photo: NPS files.
This publication has been prepared pursuant to the National Historic Preservation Act of
1966, as amended, which directs the Secretary of the Interior to develop and make
available information concerning historic properties. Technical Preservation Services
(TPS), Heritage Preservation Services Division, National Park Service prepares
standards, guidelines, and other educational materials on responsible historic
preservation treatments for a broad public.
Order Brief I Technical Preservation Services I Preservation Briefs I Search I Questions/Answers
KDW
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Preservation Brief 17: Architectural Character: Identifying the Visual Aspects of Historic ...Page 1 of 14
ti
Technical Preservation Services
Preservation National Park Service
U.S.Department of the interior
Architectural Character
Identifying the Visual Aspects of Historic
Buildings as an Aid to Preserving Their
Character qq� �
Lee H. Nelson, FAIR»Three-Step Process to Identify the Visual Character
»Step 1: Overall Visual Aspects �.
»Step 2: Visual Character at Close Range
»Step 3: Interior Spaces, Features and Finishes
»Conclusion
»The Architectural Character Checklist/Questionnaire
A NOTE TO OUR USERS:The web versions of the Preservation Briefs differ somewhat from the printed versions.
Many illustrations are new, captions are simplified, illustrations are typically in color rather than black and white, and
some complex charts have been omitted.
The Secretary of the Interior's Standards for the Treatment of Historic
Properties embody two important goals: 1) the preservation of historic materials and,
2) the preservation of a building's distinguishing character. Every old building is unique,
with its own identity and its own distinctive character. Character refers to all those visual
aspects and physical features that comprise the appearance of every historic building.
Character-defining elements include the overall shape of the building, its materials,
craftsmanship, decorative details, interior spaces and features, as well as the various
aspects of its site and environment.
The purpose of this Brief is to help the owner or the architect identify those features or
elements that give the building its visual character and that should be taken into
account in order to preserve them to the maximum extent possible.
There are different ways of understanding old buildings. They can be seen as examples
of specific building types, which are usually related to a building's function, such as
schools, courthouses or churches.
Buildings can be studied as examples of using specific materials such as concrete, wood,
steel, or limestone. They can also be considered as examples of an historical period,
which is often related to a specific architectural style, such as Gothic Revival
farmhouses, one-story bungalows, or Art Deco apartment buildings.
There are many other facets of an historic building besides its functional type, its
materials or construction or style that contribute to its historic qualities or significance.
Some of these qualities are feelings conveyed by the sense of time and place or in
buildings associated with events or people. A complete understanding of any property
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may require documentary research about its style, construction, function, its furnishings
or contents; knowledge about the original builder, owners, and later occupants; and
knowledge about the evolutionary history of the building. Even though buildings may be
of historic, rather than architectural significance, it is their tangible elements that
embody its significance for association with specific events or persons and it is those
tangible elements both on the exterior and interior that should be preserved.
Therefore, the approach taken in this Brief is limited to identifying those visual and
tangible aspects of the historic building. While this may aid in the planning process
for carrying out any ongoing or new use or restoration of the building, this approach is
not a substitute for developing an understanding about the significance of an historic
building and the district in which it is located. If the various materials, features and
spaces that give a building its visual character are not recognized and preserved, then
essential aspects of its character may be damaged in the process of change.
A building's character can be irreversibly damaged or changed in many ways, for
example, by inappropriate repointing of the brickwork, by removal of a distinctive side
porch, by changes to the window sash, by changes to the setting around the building, by
changes to the major room arrangements, by the introduction of an atrium, by painting
previously unpainted woodwork, etc.
A Three-Step Process to Identify A Building's Visual
Character
This Brief outlines a three-step approach that can be used by anyone to identify those
materials, features and spaces that contribute to the visual character of a building. This
approach involves first examining the building from afar to understand its overall setting
and architectural context; then moving up very close to appreciate its materials and the
craftsmanship and surface finishes evident in these materials; and then going into and
through the building to perceive those spaces, rooms and details that comprise its
interior visual character.
Step 1: Identify the Overall Visual Aspects
Identifying the overall visual character of a building is nothing more than looking at its
distinguishing physical aspects without focusing on its details. The major contributors to
a building's overall character are embodied in the general aspects of its setting; the
shape of the building; its roof and roof features, such as chimneys or cupolas; the
various projections on the building, such as porches or bay windows; the recesses or
voids in a building, such as open galleries, arcades, or recessed balconies; the openings
for windows and doorways; and finally the various exterior materials that contribute to
the building's character.
Step One involves looking at the building from a distance to understand the character
of its site and setting, and it involves walking around the building where that is possible.
Some buildings will have one or more sides that are more important than the others
because they are more highly visible. This does not mean that the rear of the building is
of no value whatever but it simply means that it is less important to the overall
character. On the other hand, the rear may have an interesting back porch or offer a
private garden space or some other aspect that may contribute to the visual character.
Such a general approach to looking at the building and site will provide a better
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understanding of its overall character without having to resort to an infinitely long
checklist of its possible features and details. Regardless of whether a building is
complicated or relatively plain, it is these broad categories that contribute to an
understanding of the overall character rather than the specifics of architectural features
such as moldings and their profiles.
Step 2: Identify the Visual Character at Close Range
Step Two involves looking at the building at close range or arm's length, where it is
possible to see all the surface qualities of the materials, such as their color and texture,
or surface evidence of craftsmanship or age. In some instances, the visual character is
the result of the juxtaposition of materials that are contrastingly different in their color
and texture. The surface qualities of the materials may be important because they
impart the very sense of craftsmanship and age that distinguishes historic buildings from
other buildings. Furthermore, many of these close up qualities can be easily damaged or
obscured by work that affects those surfaces. Examples of this could include painting
previously unpainted masonry, rotary disk sanding of smooth wood siding to remove
paint, abrasive cleaning of tooled stonework, or repointing reddish mortar joints with
gray portland cement.
There is an almost infinite variety of surface materials, textures and finishes that are
part of a building's character which are fragile and easily lost.
Step 3: Identify the Visual Character of Interior Spaces, Features
and Finishes
Perceiving the character of interior spaces can be somewhat more difficult than dealing
with the exterior. In part, this is because so much of the exterior can be seen at one
time and it is possible to grasp its essential character rather quickly. To understand the
interior character, Step Three says it is necessary to move through the spaces one at a
time. While it is not difficult to perceive the character of one individual room, it becomes
more difficult to deal with spaces that are interconnected and interrelated. Sometimes,
as in office buildings, it is the vestibules or lobbies or corridors that are important to the
interior character of the building. With other groups of buildings the visual qualities of
the interior are related to the plan of the building, as in a church with its axial plan
creating a narrow tunnel-like space which obviously has a different character than an
open space like a sports pavilion. Thus the shape of the space may be an essential part
of its character.
With some buildings it is possible to perceive that there is a visual linkage in a sequence
of spaces, as in a hotel, from the lobby to the grand staircase to the ballroom. Closing
off the openings between those spaces would change the character from visually linked
spaces to a series of closed spaces. For example, in a house that has a front and back
parlor linked with an open archway, the two rooms are perceived together, and this
visual relationship is part of the character of the building. To close off the open archway
would change the character of such a residence.
The importance of interior features and finishes to the character of the building should
not be overlooked. In relatively simple rooms, the primary visual aspects may be in
features such as fireplace mantels, lighting fixtures or wooden floors. In some rooms,
the absolute plainness is the character-defining aspect of the interior. So-called
secondary spaces also may be important in their own way, from the standpoint of
history or because of the family activities that occurred in those rooms. Such secondary
spaces, while perhaps historically significant, are not usually perceived as important to
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Preservation Brief 17: Architectural Character: Identifying the Visual Aspects of Historic ...Page 4 of 14
v
the visual character of the building. Thus we do not take them into account in the visual
understanding of the building.
Overall Visual Character: Shape
The shape of a building can be an important
aspect of its overall visual character. The building ;
illustrated here, for example, has a distinctive m: ' ti
horizontal boxlike shape with the middle portion r s
of the box projecting up an extra story. .. tI, t
This building has other visual aspects that help ,,
define its overall character, including the pattern : � ,, _ : � '
of vertical bands of windows, the decorative ,., "0 44 d— ti p
horizontal bands which separate the base of the WNi� �., t �', ,
building from the upper floors, the dark brown ` ;;: "`• -�- - - - h -,-
color of the brick, the large arched entranceway, - `.; .
and the castle-like tower behind the building.
Overall Visual Character: Openings
tr
i.,,,,,,,,._
, ,, �_ The opening illustrated here dominates the visual
.,� character of this building because of its size, shape,
F
location, materials, and craftsmanship. Because of
--,,,, , • • its relation to the generous staircase, this opening
*-• ,� , r.: places a strong emphasis on the principal entry to
Ala �u. `a
4,� s r , . ►arts r/ the building. Enclosing this arcade-like entry with
t e • . = glass, for example, would materially and visually
..`'` ,
3K i ` -! change the character of the building.
�
�al "Y PY
Overall Visual Character: Roof and
Related Features
This building has a number of character-defining aspects wr .. ,
which include the windows and the decorative stonework, `""'� "
but certainly the roof and its related features are visually xy. ":-
important to its overall visual character. The roof is not r.°�a , "-• "
t Isk
only highly visible, it has elaborate stone dormers, and it •
.', .� 1
also has decorative metalwork and slatework. The red and -.
black slates of differing sizes and shapes are laid in ,;_
,,-
patterns that extend around the roof of this large and -. • �- •.
P 9
freestanding building. Any changes to this patterned r' ii
slatework, or to the other roofing details would damage the 7', : .,1 _. ,,"s',.,
visual character of the building. ' ??
Overall Visual Character:
Roof and Related Features
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I
', 6 On this building, the most important visual
3 -, ,� . ,4 aspects of its character are the roof and its
.,,, _ related features , such as the dormers and
€ _ chimneys. The roof is important to the visual
` - I-,: ".`'f _. � "_ character because its steepness makes it
• 'f's e'': highly visible, and its prominence is
`�' '� f .� �- reinforced by the patterned tinwork, the six
41 :' >f dormers and the two chimneys. Changes to
i' -°: r ""' ° `- 4, .: 1 ' the roof or its features, such as removal or
, xf '`` ;.,, b alterations to the dormers, for example,
1�- -M as ; : , would certainly change the character of this
itq; .-. '; ' . i , 'A".7p .^ building. This does not discount the
importance of its other aspects, such as the
porch, the windows, the brickwork, or its setting; but the roof is clearly crucial to
understanding the overall visual character of this building as seen from a distance.
Overall Visual Character: Projections
A projecting porch or balcony can be very `.»4
important to the overall visual character of 4./i ; tv " .
r v "riE,. ,f d/`/f ..-yf Wit.
almost any building and to the district in n = is ii r
which it is located. Despite the size of this ; ; } I a
building (3-1/2 stories), and its distinctive › I .� ;y. .,
roofline profile, and despite the importance 4 -; ' , !
AITIt
of the very large window openings, the lacy A ... `:. - '"�
wrap-around iron balcony is singularly ' ` -� .
important to the visual character of this , 4 .._
building. It would seriously affect the ,� , :�- sue ,---., ,, -°
character to remove the balcony, to enclosed : - # -
it, or to replace it with a balcony lacking the `• { ` . . .:`a_
same degree of detail of the original
material.
Overall Visual Character: Trim
- N If one were to analyze the overall shape or form
of this building, it would be seen that it is a
z , , = gable-roofed house with dormers and a wrap-
r` s� � `` i c� around porch. It is similar to many other houses
4- ,Li x _ *,�;; 1 ' of the period. It is the wooden trim on the eaves
_,„ , s `� r and around the porch that gives this building its
v;,'" �-1 '
jet, f own identify and its special visual character.
z,..t? -I IfPt 8 . E .L I >`t F&i tv 5
Although such wooden trim is vulnerable to the
t. 4. s .d ' .--� X 4 w elements, and must be kept painted to prevent
E ":: `a , :-.. . _ ! deterioration; the loss of this trim would
seriously damage the overall visual character of
this building, and its loss would obliterate much of the closeup visual character so
dependent upon craftsmanship for the moldings, carvings, and the see-through jigsaw
work.
Overall Visual Character: Setting
Even architecturally modest buildings frequently
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r
will have a setting that contributes to their L2• ,+,. . --- o ,
overall character. In this very urban district, • y :SV'tz."..-'••..74.-
".
setbacks are the exception, so that the small �, I5.
front yard is something of a luxury, and it is :+ ;
important to the overall character because of its ,
design and materials, which include the iron =
fence along the sidewalk, the curved walk . ,..lim.�i1 .� ��; x,
leading to the porch, and the various plantings. '� `,. -� ` 4`h `""'"`�' A� "�`� '�
In a district where parking spaces are in great 43•'� -; z 1 . ,x. T ' " `
demand, •
such front yards are sometimes �'' ' y _ § "
converted to off-street parking, but in this ;: 1 ...i{;, gift, ,.,c. •
instance, that would essentially destroy its ' p4. i . .� V{: t •"`,-
setting and would drastically change the visual . " �--., -, 4" "'ss: ,: „`'':
character of this historic property.
Arm's Length Visual Character: Materials
""' —, ":..,.,...... � At arm's length, the visual character is most often
0 E� .*� � ,', rli x 1, determined by the surface qualities of the materials
-."TM-'" �` and craftsmanship; and while these aspects are often
' ¢�-; _ ' ft inextricably related, the original choice of materials
"""•" � �" often plays the dominant role in establishing the
7 '�� #= close range character because of the color, texture,
�;�,. _.,,. ,— ,r t or shape of the materials.
fie , � +*�`}�.F''C.
In this instance, the variety and arrangement of the
materials is important in defining the visual character, starting with the large pieces of
broken stone which form the projecting base for the building walls, then changing to a
wall of roughly rectangular stones which vary in size, color, and texture, all with
accentuated, projecting beads of mortar, then there is a rather precise and narrow band
of cut and dressed stones with minimal mortar joints, and finally, the main building walls
are composed of bricks, rather uniform in color, with fairly generous mortar joints. It is
the juxtaposition and variety of these materials (and of course, the craftsmanship) that
is very important to the visual character. Changing the raised mortar joints, for
example, would drastically alter the character at arm's length.
Arm's Length Visual Character: Craft Details
There are many instances where craft details z
dominate the arms length visual character. As seen r. /„ ;.
tn
here, the craft details are especially noticeable y �,
because the stones are all of a uniform color, and x-,r> , .7 s 37',.'.
they are all squared off, but their surfaces were 4 ,
worked with differing tools and techniques to create a 'r 3 - ;:`.
great variety of textures, resulting in a tour-de-force ; , E3
of craft details. This texture is very important at close
range. It was a deliberately contrived surface that is
I-
an important contributor to the visual character of 421,
this building. ,
Interior Visual Character: Individually Important Spaces
In assessing the interior visual character of any
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x, s historic building, it is necessary to ask whether
7,,,; there are spaces that are important to the
character of this particular building, whether the
building is architecturally rich or modest, or even if
{" * i �' it •is •a simple or utilitarian structure.
s . v
( e ', ' The character of the individuallyimportant
f , . ' m --- space, which is illustrated here, is a combination of
°' ,4 1 "' its size, the twin curving staircases, the massive
columns and curving vaulted ceilings, in addition to
the quality of the materials in the floor and in the
stairs. If the ceiling were to be lowered to provide
space for heating ducts, or if the stairways were to be enclosed for code reasons, the
shape and character of this space would be damaged, even if there was no permanent
physical damage. Such changes can easily destroy the visual character of an individually
important interior space. Thus, it is important that the visual aspects of a building's
interior character be recognized before planning any changes or alterations.
Interior Visual Character: Related Spaces
P27
Many buildings have interior spaces that are
visual) or physically related so that, asyou r '1
Y PY Y � "
move through them, they are perceived not as ,x 1`�'ki t'
separate spaces, but as a sequence of related ,Y' ' T `-
spaces that are important in defining the k fp
interior character of the building. The example t ,
which is illustrated here consists of two spaces £A ,„ ,}A, .•
that are visually linked to each other. 7 *=>;° , I.
,�
The.top photo shows a vestibule which is of a �� i — -.
generous size and unusual in its own right, but .. i '1"`'
more important, it visually relates to the `
staircase off of it.
The stairway, bottom photo, is the second part of this sequence of t ," Ic1 s .
related spaces, and it provides continuing access to the upper floors. f=
These related spaces are very important in defining the interior
character of this building. Almost any change to these spaces, such Y = '
as installing doors between the vestibule and the hallway, or isFi.' ' ��
enclosing the stair would seriously impact their character and the ,
way that character is perceived. ui'
!,,0,
t
Interior Visual Character: Interior Features
Interior features are three-dimensional building elements or
architectural details that are an integral part of the building as
opposed to furniture. Interior features are often important in
defining the character of an individual room or space. In some
instances, an interior feature, like a large and ornamental
open stairway may dominate the visual character of an entire
building. In other instances, a modest iron stairway (like the
one illustrated here) may be an important interior feature,
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v
and its preservation would be crucial to preserving the interior
;,, character of the building.
,(AV l '1.. Such features can also include the obvious things like
1 ,:,, A%r , '! fireplace mantles, plaster ceiling medallions, or paneling, but
Y 1 kti s , .{ they also' ! _ '#I';, �4''}f bank tellers cages, decorative elevator doors, etc.lighting fixtures,
...mot�,, • t , L f-/
' � ..' ;s , Interior Visual Character: Surface Materials and
pt
r " \ i _ '' Finishes
dui ? A .
v-- x 4 g When identifying the visual ' , .:
character of historic ,
interior spaces one should not overlook the �-
importance of those materials and finishes that yf
comprise the surfaces of walls, floors and ceilings. :
The surfaces may have evidence of either handcraft . .. ,. J°4
x•i t
or machine made products that are important A _ - > '
contributors to the visual character, including • "x _ y `
Patterned or inlaid designs in the wood flooring,
decorative painting practices such as stenciling, *« ' " ._
imitation marble or wood grain, wallpapering,
tinwork, tile floors, etc.
The example illustrated here involves a combination of real marble at the base of the
column, imitation marble patterns on the plaster surface of the column (a practice called
scagliola), and a tile floor surface that uses small mosaic tiles arranged to form
geometric designs in several different colors. While such decorative materials and
finishes may be important in defining the interior visual character of this particular
building, it should be remembered that in much more modest buildings, the plainness of
surface materials and finishes may be an essential aspect of their historic character.
Interior: Exposed Structure
- If features of the structural system are
exposed, such as loadbearing brick walls, cast
. , - r - iron columns, roof trusses, posts and beams,
( vigas, or stone foundation walls, they may be
I ` �1 important in defining the building's interior
1 ' ,4, z visual character.
I. 3 "°'s s ./, , ,, _a..-�`
Fragility of A Building's Visual Character
Some aspects of a building's visual character are fragile and are
easily lost. This is true of brickwork, for example, which can be
irreversibly damaged with inappropriate cleaning techniques or by
insensitive repointing practices. At least two factors are important
contributors to the visual character of brickwork, namely the brick
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itself and the craftsmanship. Between these, there are many more
aspects worth noting, such as color range of bricks, size and shape
variations, texture, bonding patterns, together with the many
variable qualities of the mortar joints, such as color, width of joint
and tooling.
These qualities could be easily damaged by painting the brick, by
raking out the joint with power tools, or repointing with a joint that . xY"`"
is too wide. As seen here during the process of repointing, the visual ' .
character of this front wall is being dramatically changed from a wall woi jit.4
where the bricks predominate, to a wall that is visually dominated
by the mortar joints. ,
VI
Conclusion
Using this three-step approach, it is possible to conduct a walk through and identify all
those elements and features that help define the visual character of the building. In
most cases, there are a number of aspects about the exterior and interior that are
important to the character of an historic building. The visual emphasis of this brief will
make it possible to ascertain those things that should be preserved because their loss or
alteration would diminish or destroy aspects of the historic character whether on the
outside, or on the inside of the building.
The Architectural Character Checklist/Questionnaire
This checklist can be taken to the building and used to identify those aspects that give
the building and setting its essential visual qualities and character. This checklist
consists of a series of questions that are designed to help in identifying those things that
contribute to a building's character. The use of this checklist involves the threestep
process of looking for: 1) the overall visual aspects, 2) the visual character at close
range, and 3) the visual character of interior spaces, features and finishes.
Because this is a process to identify architectural character, it does not address those
intangible qualities that give a property or building or its contents its historic
significance, instead this checklist is organized on the assumption that historic
significance is embodied in those tangible aspects that include the building's setting, its
form and fabric.
STEP ONE
1. Shape
What is there about the form or shape of the building that gives the building its identity?
Is the shape distinctive in relation to the neighboring buildings? Is it simply a low, squat
box, or is it a tall, narrow building with a corner tower? Is the shape highly consistent
with its neighbors? Is the shape so complicated because of wings, or ells, or differences
in height, that its complexity is important to its character? Conversely, is the shape so
simple or plain that adding a feature like a porch would change that character? Does the
shape convey its historic function as in smoke stacks or silos?
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Notes on the Shape or Form of the Building:
2. Roof and Roof Features
Does the roof shape or its steep (or shallow) slope contribute to the building's character?
Does the fact that the roof is highly visible (or not visible at all) contribute to the
architectural identity of the building? Are certain roof features important to the profile of
the building against the sky or its background, such as cupolas, multiple chimneys,
dormers, cresting, or weather vanes? Are the roofing materials or their colors or their
patterns (such as patterned slates) more noticeable than the shape or slope of the roof?
Notes on the Roof and Roof Features:
3. Openings
Is there a rhythm or pattern to the arrangement of windows or other openings in the
walls; like the rhythm of windows in a factory building, or a threepart window in the
front bay of a house; or is there a noticeable relationship between the width of the
window openings and the wall space between the window openings? Are there distinctive
openings, like a large arched entranceway, or decorative window lintels that accentuate
the importance the window openings, or unusually shaped windows, or patterned
window sash, like small panes of glass in the windows or doors, that are important to
the character? Is the plainness of the window openings such that adding shutters or
gingerbread trim would radically change its character? Is there a hierarchy of facades
that make the front windows more important than the side windows? What about those
walls where the absence of windows establishes its own character?
Notes on the Openings:
4. Projections
Are there parts of the building that are characterdefining because they project from the
walls of the building like porches, cornices, bay windows, or balconies? Are there turrets,
or widely overhanging eaves, projecting pediments or chimneys?
Notes on the Projections:
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5. Trim and Secondary Features
Does the trim around the windows or doors contribute to the character of the building?
Is there other trim on the walls or around the projections that, because of its decoration
or color or patterning contributes to the character of the building? Are there secondary
features such as shutters, decorative gables, railings, or exterior wall panels?
Notes on the Trim and Secondary Features:
6. Materials
Do the materials or combination of materials contribute to the overall character of the
building as seen from a distance because of their color or patterning, such as broken
faced stone, scalloped wall shingling, rounded rock foundation walls, boards and
battens, or textured stucco?
Notes on the Materials
7. Setting
What are the aspects of the setting that are important to the visual character? For
example, is the alignment of buildings along a city street and their relationship to the
sidewalk the essential aspect of its setting? Or, conversely, is the essential character
dependent upon the tree plantings and out buildings which surround the farmhouse? Is
the front yard important to the setting of the modest house? Is the specific site
important to the setting such as being on a hilltop, along a river, or, is the building
placed on the site in such a way to enhance its setting? Is there a special relationship to
the adjoining streets and other buildings? Is there a view? Is there fencing, planting,
terracing, walkways or any other landscape aspects that contribute to the setting?
Notes on the Setting:
STEP TWO
8. Materials at Close Range
Are there one or more materials that have an inherent texture that contributes to the
close range character, such as stucco, exposed aggregate concrete, or brick textured
with vertical grooves? Or materials with inherent colors such as smooth orange colored
brick with dark spots of iron pyrites, or prominently veined stone, or green serpentine
stone? Are there combinations of materials, used in juxtaposition, such as several
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different kinds of stone, combinations of stone and brick, dressed stones for window
lintels used in conjunction with rough stones for the wall? Has the choice of materials or
the combinations of materials contributed to the character?
Notes on the Materials at Close Range:
9. Craft Details
Is there high quality brickwork with narrow mortar joints? Is there hand tooled or
patterned stonework? Do the walls exhibit carefully struck vertical mortar joints and
recessed horizontal joints? Is the wall shinglework laid up in patterns or does it retain
evidence of the circular saw marks or can the grain of the wood be seen through the
semitransparent stain? Are there hand split or handdressed clapboards, or machine
smooth beveled siding, or wood rusticated to look like stone, or Art Deco zigzag designs
executed in stucco?
Almost any evidence of craft details, whether handmade or machinemade, will
contribute to the character of a building because it is a manifestation of the materials, of
the times in which the work was done, and of the tools and processes that were used. It
further reflects the effects of time, of maintenance (and/or neglect) that the building has
received over the years. All of these aspects are a part of the surface qualities that are
seen only at close range.
Notes on the Craft Details:
STEP THREE
10. Individual Spaces
Are there individual rooms or spaces that are important to this building because of their
size, height, proportion, configuration, or function, like the center hallway in a house, or
the bank lobby, or the school auditorium, or the ballroom in a hotel, or a courtroom in a
county courthouse?
Notes on the Individual Spaces.
11. Related Spaces and Sequences of Spaces
Are there adjoining rooms that are visually and physically related with large doorways or
open archways so that they are perceived as related rooms as opposed to separate
rooms? Is there an important sequence of spaces that are related to each other, such as
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the sequence from the entry way to the lobby to the stairway and to the upper balcony
as in a theatre; or the sequence in a residence from the entry vestibule to the hallway to
the front parlor, and on through the sliding doors to the back parlor; or the sequence in
an office building from the entry vestibule to the lobby to the bank of elevators?
Notes on the Related Spaces and Sequences of Spaces:
12. Interior Features
Are there interior features that help define the character of the building, such as
fireplace mantels, stairways and balustrades, arched openings, interior shutters,
inglenooks, cornices, ceiling medallions, light fixtures, balconies, doors, windows,
hardware, wainscoting, panelling, trim, church pews, courtroom bars, teller cages,
waiting room benches?
Notes on the Interior Features:
13. Surface Finishes and Materials
Are there surface finishes and materials that can affect the design, the color or the
texture of the interior? Are there materials and finishes or craft practices that contribute
to the interior character, such as wooden parquet floors, checkerboard marble floors,
pressed metal ceilings, fine hardwoods, grained doors or marbleized surfaces, or
polychrome painted surfaces, or stenciling, or wallpaper that is important to the historic
character? Are there surface finishes and materials that, because of their plainness, are
imparting the essential character of the interior such as hard or bright, shiny wall
surfaces of plaster or glass or metal?
Notes on the Surface Finishes and Materials:
14. Exposed Structure
Are there spaces where the exposed structural elements define the interior character
such as the exposed posts, beams, and trusses in a church or train shed or factory? Are
there rooms with decorative ceiling beams (nonstructural) in bungalows, or exposed
vigas in adobe buildings?
Notes on the Exposed Structure:
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This concludes the three-step process of identifying the visual aspects of historic
buildings and is intended as an aid in preserving their character and other distinguishing
qualities. It is not intended as a means of understanding the significance of historical
properties or districts, nor of the events or people associated with them. That can only
be done through other kinds of research and investigation.
Acknowledgements
This Preservation Brief was originally developed as a slide talk/methodology in 1982 to discuss the use of the
Secretary of the Interior's Standards for Rehabilitation in relation to preserving historic character; and it was
amplified and modified in succeeding years to help guide preservation decision making,initially for maintenance
personnel in the National Park Service.
Please note that many of the figures that were in the printed Brief had to be omitted here; however you
can go to a special web site,The Walk-Through--Identifying the Visual Character of Historic Buildings,to
study all of Lee Nelson's photos and text presented as a long distance learning program.
A number of people contributed to the evolution of the ideas presented here. Special thanks go to Emogene Bevitt
and Gary Hume, primarily for the many and frequent discussions relating to this approach in its evolutionary stages;
to Mark Fram,Ontario Heritage Foundation,Toronto,for suggesting several additions to the Checklist; and more
recently,to my coworkers, both in Washington and in our regional offices,especially Ward Jandl, Sara Blumenthal,
Charles Fisher,Sharon Park,AIA,Jean Travers, Camille Martone,Susan Dynes, Michael Auer,Anne Grimmer, Kay
Weeks, Betsy Chittenden, Patrick Andrus,Carol Shull, Hugh Miller, FAIA,Jerry Rogers, Paul Alley, David Look,AIA,
Margaret Pepin-Donat, Bonnie Halda, Keith Everett,Thomas Keohan,the Preservation Services Division, MidAtlantic
Region,and several reviewers in state preservation offices,especially Ann Haaker,Illinois; and Stan Graves,AIA,
Texas; for providing very critical and constructive review of the manuscript.
Washington,D.C.September, 1988
Home page logo: Close-up of stone wall,showing craftsmanship. Photo: NPS files.
This publication has been prepared pursuant to the National Historic Preservation Act of
1966, as amended, which directs the Secretary of the Interior to develop and make
available information concerning historic properties. Technical Preservation Services
(TPS), Heritage Preservation Services Division, National Park Service prepares
standards, guidelines, and other educational materials on responsible historic
preservation treatments for a broad public.
Order Brief I Technical Preservation Services I Preservation Briefs I Search I Questions/Answers
KDW
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• Preservation Brief 32: Making Historic Properties Accessible Page 1 of 13
Technical Preservation Services
r di Preservation BriefsNational Park Servicetnki
'.
U.S.Department of the interior
Making Historic Properties Accessible
rrtrrr ''
Thomas C. Jester and Sharon C. Park, AIA ,to
»Planning Accessibility Modifications
»Review the Historical Significance
»Assess Existing and Required Accessibility 84
»Identify and Evaluate Accessibility Options 4.1
»Accessibility Solutions
»The Building Site
»Considering a New Entrance
»Moving Through Historic Interiors
»Building Amenities
»Federal Accessibility Laws
»Conclusion
»Additional Reading
A NOTE TO OUR USERS:The web versions of the Preservation Briefs differ somewhat from the printed versions.
Many illustrations are new, captions are simplified, illustrations are typically in color rather than black and white, and
some complex charts have been omitted.
Historically, most buildings and landscapes were not designed to be readily
accessible for people with disabilities. In recent years, however, emphasis has been
placed on preserving historically significant properties, and on making these properties-
and the activities within them-more accessible to people with disabilities. With the
passage of the Americans with Disabilities Act in 1990, access to properties open to the
public is now a civil right.
This Preservation Brief introduces the complex issue
al of providing accessibility at historic properties, and
underscores the need to balance accessibility and
historic preservation. It provides guidance on making
historic properties accessible while preserving their
.,. historic character; the Brief also provides examples to
show that independent physical accessibility at
n + historic properties can be achieved with careful
"-• planning, consultation, and sensitive design. While
7° ""t "' fv the Brief focuses primarily on making buildings and
their sites accessible, it also includes a section on
historic landscapes. The Brief will assist historic
A significant entrance may be difficult property owners, design professionals, and
to modify.Although a special administrators in evaluating their historic properties
challenge,always sensitivee changes can so that the highest level of accessibilitycan be
almost be made to provide g
access while preserving the unique provided while minimizing changes to historic
historic character. Photo: NPS files. materials and features. Because many projects
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Preservation Brief 32: Making Historic Properties Accessible Page 2 of 13
encompassing accessibility work are complex, it is
advisable to consult with experts in the fields of historic preservation and accessibility
before proceeding with permanent physical changes to historic properties.
Modifications to historic properties to increase accessibility may be as simple as a small,
inexpensive ramp to overcome one entrance step, or may involve changes to exterior
and interior features. The Brief does not provide a detailed explanation of local or State
accessibility laws as they vary from jurisdiction to jurisdiction. A concise explanation of
several federal accessibility laws is included below.
Planning Accessibility Modifications
Historic properties are distinguished by features, materials, spaces, and spatial
relationships that contribute to their historic character. Often these elements, such as
steep terrain, monumental steps, narrow or heavy doors, decorative ornamental
hardware, and narrow pathways and corridors, pose barriers to persons with disabilities,
particularly to wheelchair users.
A three-step approach is recommended to identify and implement accessibility
modifications that will protect the integrity and historic character of historic properties:
1) Review the historical significance of the property and identify character-defining
features; 2) Assess the property's existing and required level of accessibility; and
3) Evaluate accessibility options within a preservation context.
1) Review the Historical Significance of the Property
If the property has been designated as historic
(properties that are listed in, or eligible for listing in � 4.4'r
the National Register of Historic Places, or designated
under State or local law), the property's nomination fr ,F
file should be reviewed to learn about its significance. -- l :
Local preservation commissions and State Historic
•
Preservation Offices can usually provide copies of the
nomination file and are also resources for additional
,Fir
information and assistance. Review of the written
documentation should always be supplemented with a
physical investigation to identify which character ..- '
Y b
•
defining features and spaces must be protected
whenever any changes are anticipated. If the level of This accessibility ramp is compatible
documentation for a property's significance is limited, with the historic building in scale and
it may be necessary to have a preservation materials. Photo:William Smith.
professional identify specific historic features, materials, and spaces that should be
protected.
For most historic properties, the construction materials, the form and style of the
property, the principal elevations, the major architectural or landscape features, and the
principal public spaces constitute some of the elements that should be preserved. Every
effort should be made to minimize damage to the materials and features that convey a
property's historical significance when making modifications for accessibility. Very small
or highly significant properties that have never been altered may be extremely difficult
to modify.
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Secondary spaces and finishes and features that may be less important to the historic
character should also be identified; these may generally be altered without jeopardizing
the historical significance of a property. Nonsignificant spaces, secondary pathways,
later additions, previously altered areas, utilitarian spaces, and service areas can usually
be modified without threatening or destroying a property's historical significance.
2) Assess the Property's Existing and Required Level of Accessibility
A building survey or assessment will provide a thorough evaluation of a property's
accessibility. Most surveys identify accessibility barriers in the following areas: building
and site entrances; surface textures, widths and slopes of walkways; parking; grade
changes; size, weight and configuration of doorways; interior corridors and path of
travel restrictions; elevators; and public toilets and amenities. Simple audits can be
completed by property owners using readily available checklists (See Further Reading).
Accessibility specialists can be hired to assess barriers in more complex properties,
especially those with multiple buildings, steep terrain, or interpretive programs. Persons
with disabilities can be particularly helpful in assessing specific barriers.
All applicable accessibility requirements--local codes, State codes and federal laws--
should be reviewed carefully before undertaking any accessibility modification. Since
many States and localities have their own accessibility regulations and codes (each with
their own requirements for dimensions and technical requirements), owners should use
the most stringent accessibility requirements when implementing modifications. The
Americans with Disability Act Accessibility Guidelines (ADAAG) is the document that
should be consulted when complying with the Americans with Disabilities Act (ADA)
requirements.
3) Identify and Evaluate Accessibility Options within a Preservation Context
Once a property's significant materials and features have been identified, and existing
and required levels of accessibility have been established, solutions can be developed.
Solutions should provide the greatest amount of accessibility without threatening or
destroying those materials and features that make a property significant. Modifications
may usually be phased over time as funds are available, and interim solutions can be
considered until more permanent solutions are implemented. A team comprised of
persons with disabilities, accessibility and historic preservation professionals, and
building inspectors should be consulted as accessibility solutions are developed.
Modifications to improve accessibility should generally be based on the following
priorities:
1) Making the main or a prominent public entrance and primary public spaces
accessible, including a path to the entrance; 2) Providing access to goods,
services, and programs; 3) Providing accessible restroom facilities; and, 4)
Creating access to amenities and secondary spaces.
All proposed changes should be evaluated for
conformance with the Secretary of the Interior's
"Standards for the Treatment of Historic Properties,"
which were created for property owners to guide
preservation work. These Standards stress the
importance of retaining and protecting the materials and
features that convey a property's historical significance.
Thus, when new features are incorporated for
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Preservation Brief 32: Making Historic Properties Accessible Page 4 of 13
0
,� , - ,,,= accessibility, historic materials and features should be
R'4 it }1 , , retained whenever possible. Accessibility modifications
,fj,
t .`;4 f . should be in scale with the historic property, visually
.. = itYllTtis l<<! '1 ` compatible, and, whenever possible, reversible.
1I � 4 \ Reversible means that if the new feature were removed
, . '_' ,,-. at a later date, the essential form and integrity of the
;<:.x�. .4 U.
,ml, I ; property would be unimpaired. The design of new
, I l' �.� ,:l 1 features should also be differentiated from the design of
— ? i
�� �4�'ar; 3'�* �, i the historic property so that the evolution of the property
i ovIt i° 3= (I. is evident.
, , ""`�; '''" x In general, when historic properties are altered, they
k f'
e should be made as accessible as possible. However, if an
' �.,1 owner or a project team believes that certain
The ramps scale and materials are modifications would threaten or destroy the significance
inconsistent with the historic of the property, the State Historic Preservation Officer
character of the building. Photo: should be consulted to determine whether or not any
NPS files.
special accessibility provisions may be used. Special
accessibility provisions for historic properties will vary depending on the applicable
accessibility requirements.
In some cases, programmatic access may be the only option for extremely small or
unaltered historic properties, such as a two-story house museum with no internal
elevator. Programmatic access for historic properties refers to alternative methods of
providing services, information, and experiences when physical access cannot be
provided. It may mean offering an audio-visual program showing an inaccessible upper
floor of a historic house museum, providing interpretive panels from a vista at an
inaccessible terraced garden, or creating a tactile model of a historic monument for
people with visual impairments.
Accessibility Solutions
The goal in selecting appropriate solutions for specific historic properties is to provide a
high level of accessibility without compromising significant features or the overall
character of the property. The following sections describe accessibility solutions and
offer guidance on specific historic property components, namely the building site,
entrances, interiors, landscapes, amenities, and new additions. Several solutions are
discussed in each section, referencing dimensions and technical requirements from the
ADA's accessibility guidelines, ADAAG. State and local requirements, however, may
differ from the ADA requirements. Before making any modification owners should be
aware of all applicable accessibility requirements.
The Building Site
An accessible route from a parking lot, sidewalk, and public street to the entrance of a
historic building or facility is essential. An accessible route, to the maximum extent
possible, should be the circulation route used by the general public. Critical elements of
accessible routes are their widths, slopes, cross slopes, and surface texture. Each of
these route elements must be appropriately designed so that the route can be used by
everyone, including people with disabilities. The distance between the arrival and
destination points should also be as short as
possible. Sites containing designed landscapes
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Preservation Brief 32: Making Historic Properties Accessible Page 5 of 13
,
ga , ..... �; should be carefully evaluated before making
t
accessibility modifications. Historic landscapes
lw -` ,. s ' R are described in greater detail below.
f I Providing Convenient Parking. If parking is
-1. r ,, i provided, it should be as convenient as possible
1 ,I Mp F9 ,4, "3t.r.* F`� for people with disabilities. Specially designated
i k i £ L i Q 3 1 I'-' nd 3 S Rf —gJ A 1, _y parking can often be created to improve
�.,.,,_ ._ `- . accessibility. Modifications to parking
a ' '' configurations and pathways should not alter
r 1 significant landscape features.
The significant building site is now
accessible to people with disabilities(note
steps in front of ramp). Photo: NPS files. Creating an Accessible Route. The route or
path through a site to a historic building's
entrance should be wide enough, generally at least 3 feet (91 cm), to accommodate
visitors with disabilities and must be appropriately graded with a stable, firm, and slip-
resistant surface. Existing paths should be modified to meet these requirements
whenever possible as long as doing so would not threaten or destroy significant
materials and features.
Existing surfaces can often be stabilized by providing a new base and resetting the
paving materials, or by modifying the path surface. In some situations it may be
appropriate to create a new path through an inaccessible area. At large properties, it
may be possible to regrade a slope to less than 1:20 (5%), or to introduce one or more
carefully planned ramps. Clear directional signs should mark the path from arrival to
destination.
Entrances
Whenever possible, access to historic buildings should be through a primary public
entrance. In historic buildings, if this cannot be achieved without permanent damage to
character-defining features, at least one entrance used by the public should be made
accessible. If the accessible entrance is not the primary public entrance, directional signs
should direct visitors to the accessible entrance. A rear or service entrance should be
avoided as the only mean of entering a building.
Creating an accessible entrance usually involves overcoming a
change in elevation. Steps, landings, doors, and thresholds, all part
of the entrance, often pose barriers for persons with disabilities. To
preserve the integrity of these features, a number of solutions are
1 available to increase accessibility. Typical solutions include
regrading, incorporating ramps, installing wheelchair lifts, creating
new entrances, and modifying doors, hardware, and thresholds.
x j A'` ` ' Regrading an Entrance. In some cases, when the entrance steps
1 - and landscape features are not highly significant, it may be possible
.: . to regrade to provide a smooth entrance into a building. If the
i ' 'r existing steps are historic masonry, they should be buried, whenever
' , ‘` - possible, and not removed.
The historic
threshold was made Incorporating Ramps.
accessible with a Permanent ramps are
1/2"wood bevel.
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Preservation Brief 32: Making Historic Properties Accessible Page 6 of 13
Photo: NPS files. perhaps the most common W ,-, � -
means to make an entrance 7 r , lE„ 1
accessible. As a new feature, ramps should be x ,;�
carefully designed and appropriately located to ,,,
preserve a property's historic character. if 444
Ramps should be located at public entrances = w..A F '
used by everyone whenever possible, preferably - ���� ' •� x
where there is minimal change in grade. Ramps I Y
should also be located to minimize the loss of '��
,0-0,-�' ^�*, -;4.-• r "" Wry°r+A. ,. 'Ibrt',
historic features at the connection points-porch a r.,. .X.,a .�, ,.�.4 �,
railings, steps, and windows-and should preserve A new elevator entrance was provided next
the overall historic setting and character of the to p
the the servicesstairs insideto . Photo:rovideuniversal Courtesyaccess GSA.to
property. Larger buildings may have below grade
areas that can accommodate a ramp down to an entrance. Below grade entrances can
be considered if the ramp leads to a publicly used interior, such as an auditorium, or if
the building is serviced by a public elevator. Ramps can often be incorporated behind
historic features, such as cheek-walls or railings, to minimize the visual effect.
The steepest allowable slope for a ramp is usually 1:12 (8%), but gentler slopes should
be used whenever possible to accommodate people with limited strength. Greater
changes in elevation require larger and longer ramps to meet accessibility scoping
provisions and may require an intermediate landing. Most codes allow a slightly steeper
ramp for historic buildings to overcome one step.
Ramps can be faced with a variety of materials, including wood, brick, and stone. Often
the type and quality of the materials determines how compatible a ramp design will be
with a historic property. Unpainted pressure-treated wood should not be used to
construct ramps because it usually appears temporary and is not visually compatible
with most historic properties.
Railings should be simple in design, distinguishable from other historic features, and
should extend one foot beyond the sloped area.
Ramp landings must be large enough for wheelchair users, usually at least 5 feet by 5
feet (152.5 cm by 152.5 cm), and the top landing must be at the level of the door
threshold. It may be possible to reset steps by creating a ramp to accommodate minor
level changes and to meet the threshold without significantly altering a property's
historic character. If a building's existing landing is not wide or deep enough to
accommodate a ramp, it may be necessary to modify the entry to create a wider
landing. Long ramps, such as switchbacks, require intermediate landings, and all ramps
should be detailed with an appropriate edge and railing for wheelchair users and visually
impaired individuals.
Temporary or portable ramps are usually constructed of light-weight materials and,
thus, are rarely safe or visually compatible with historic properties. Moreover, portable
ramps are often stored until needed and, therefore, do not meet accessibility
requirements for independent access. Temporary and portable ramps, however, may be
an acceptable interim solution to improve accessibility until a permanent solution can be
implemented.
Installing Wheelchair Lifts. Platform lifts and inclined stair lifts, both of which
accommodate only one person, can be used to overcome changes of elevation ranging
from three to 10 feet (.9 m-3 m) in height. However, many States have restrictions on
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Preservation Brief 32: Making Historic Properties Accessible Page 7 of 13
the use of wheelchair lifts, so all applicable codes should be reviewed carefully before
installing one. Inclined stair lifts, which carry a wheelchair on a platform up a flight of
stairs, may be employed selectively. They tend to be visually intrusive, although they
are relatively reversible. Platform lifts can be used when there is inadequate space for a
ramp. However, such lifts should be installed in unobtrusive locations and under cover to
minimize maintenance if at all possible. A similar, but more expensive platform lift has a
retracting railing that lowers into the ground, minimizing the visual effect to historic
properties. Mechanical lifts have drawbacks at historic properties with high public
visitation because their capacity is limited, they sometimes cannot be operated
independently, and they require frequent maintenance.
Considering a New Entrance. When it is not possible to modify an existing entrance,
it may be possible to develop a new entrance by creating an entirely new opening in an
appropriate location, or by using a secondary window for an opening. This solution
should only be considered after exhausting all possibilities for modifying existing
entrances.
Retrofitting Doors. Historic doors generally should not be replaced, nor should door
frames on the primary elevation be widened, as this may alter an important feature of a
historic design. However, if a building's historic doors have been removed, there may be
greater latitude in designing a compatible new entrance. Most accessibility standards
require at least a 32" (82 cm) clear opening with manageable door opening pressures.
The most desirable preservation solution to improve accessibility is retaining historic
doors and upgrading the door pressure with one of several devices. Automatic door
openers (operated by push buttons, mats, or electronic eyes) and power-assisted door
openers can eliminate or reduce door pressures that are accessibility barriers, and make
single or double-leaf doors fully operational.
Adapting Door Hardware. If a door opening is within an •
inch or two of meeting the 32" (81 cm) clear opening
requirement, it may be possible to replace the standardOr AY
hinges with off-set hinges to increase the size of the door .1 �� �� :_
opening as much as 1 1 (3.8 cm). Historic hardware can
be retained in place, or adapted with the addition of an
automatic opener, of which there are several types. Door ;
hardware can also be retrofitted to reduce door pressures.
For example, friction hinges can be retrofitted with ball- • �`•
bearing inserts, and door closers can be rethreaded to • •: .••• ••
reduce the door pressure. s� :`
Altering Door Thresholds. A door threshold that exceeds
the allowable height, generally 1/2" (1.3 cm), can be altered 1 :tea
or removed with one that meets applicable accessibility This door handle has been
requirements. If the threshold is deemed to be significant, retrofitted to meet ADA
a bevel can be added on each side to reduce its height. requirements. Photo: NPS files.
Another solution is to replace the threshold with one that meets applicable accessibility
requirements and is visually compatible with the historic entrance.
Readily Acheivable Accesibility Options
Many accessibility solutions can be implemented easily and inexpensively without
destroying the significance of historic properties. While it may not be possible to
undertake all of the modifications listed below, each change will improve accessibility.
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Preservation Brief 32: Making Historic Properties Accessible Page 8 of 13
Sites and Entrances
• Creating a designated parking space.
• Installing ramps.
• Making curb cuts.
Interiors
• Repositioning shelves.
• Rearranging tables, displays, and furniture.
• Repositioning telephones.
• Adding raised markings on elevator control buttons.
• Installing flashing alarm lights.
• Installing offset hinges to widen doorways.
• Installing or adding accessible door hardware.
• Adding an accessible water fountain, or providing a paper cup dispenser at an
inaccessible water fountain.
Restrooms
• Installing grab bars in toilet stalls.
• Rearranging toilet partitions to increase maneuvering space.
• Insulating lavatory pipes under sinks to prevent burns.
• Installing a higher toilet seat.
• Installing a full-length bathroom mirror.
• Repositioning the paper towel dispenser.
Moving Through Historic Interiors
Persons with disabilities should have independent access f
to all public areas and facilities inside historic buildings.
The extent to which a historic interior can be modified
depends on the significance of its materials, plan, spaces,
features, and finishes. Primary spaces are often more
difficult to modify without changing their character.
Secondary spaces may generally be changed without --= -
compromising a building's historic character. Signs should `
clearly mark the route to accessible restrooms,
telephones, and other accessible areas.
InstallingRamps and Wheelchair Lifts. If space building gfoye lift was cor reated
d historic
P P foyer created using
permits, ramps and wheelchair lifts can also be used to "like" materials. Photo: NPS files.
increase accessibility inside buildings. However, some
States and localities restrict interior uses of wheelchair lifts for life-safety reasons. Care
should be taken to install these new features where they can be readily accessed.
Ramps and wheelchair lifts are described below.
Upgrading Elevators. Elevators are an efficient means of providing accessibility
between floors. Some buildings have existing historic elevators that are not adequately
accessible for persons with disabilities because of their size, location, or detailing, but
they may also contribute to the historical significance of a building. Significant historic
elevators can usually be upgraded to improve accessibility. Control panels can be
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Preservation Brief 32: Making Historic Properties Accessible Page 9 of 13
modified with a "wand" on a cord to make the control panel accessible, and timing
devices can usually be adjusted.
Retrofitting Door Knobs. Historic door knobs and other hardware may be difficult to
grip and turn. In recent years, lever-handles have been developed to replace door
knobs. Other lever-handle devices can be added to existing hardware. If it is not
possible or appropriate to retrofit existing door knobs, doors can be left open during
operating hours (unless doing so would violate life safety codes), and power-assisted
door openers can be installed. It may only be necessary to retrofit specific doorknobs to
create an accessible path of travel and accessible restrooms.
Modifying Interior Stairs. Stairs are the primary barriers for many people with
disabilities. However, there are some ways to modify stairs to assist people who are able
to navigate them. It may be appropriate to add hand railings if none exist. Railings
should be 1 1/4" (3.8 cm) in diameter and return to the wall so straps and bags do not
catch. Color-contrasting, slip-resistant strips will help people with visual impairments.
Finally, beveled or closed risers are recommended unless the stairs are highly
significant, because open risers catch feet.
Building Amenities
Some amenities in historic buildings, such as restrooms, seating, telephones, drinking
fountains, counters, may contribute to a building's historic character. They will often
require modification to improve their use by persons with disabilities. In many cases,
supplementing existing amenities, rather than changing or removing them, will increase
access and minimize changes to historic features and materials.
Upgrading Restrooms. Restrooms may have historic fixtures such as sinks, urinals, or
marble partitions that can be retained in the process of making modifications. For
example, larger restrooms can sometimes be reconfigured by relocating or combining
partitions to create an accessible toilet stall. Other changes to consider are adding grab
bars around toilets, covering hot water pipes under sinks with insulation to prevent
burns, and providing a sink, mirror, and paper dispenser at a height suitable for
wheelchair users. A unisex restroom may be created if it is technically infeasible to
create two fully accessible restrooms, or if doing so would threaten or destroy the
significance of the building. It is important to remember that restroom fixtures, such as
sinks, urinals, and partitions, may be historic, and therefore, should be preserved
whenever possible.
Modifying Other Amenities. Other amenities inside historic buildings may require
modification. Seating in a theater, for example, can be made accessible by removing
some seats in several areas. New seating that is accessible can also be added at the end
of existing rows, either with or without a level floor surface. Readily removable seats
may be installed in wheelchair spaces when the spaces are not required to accommodate
wheelchair users. Historic water fountains can be retained and new, two-tiered fountains
installed if space permits. If public telephones are provided, it may be necessary to
install at least a Text Telephone (TT), also known as a Telecommunication Device for the
Deaf (TDD. Historic service counters commonly found in banks, theaters, and hotels
generally should not be altered. It is preferable to add an accessible counter on the end
of a historic counter if feasible. Modified or new counters should not exceed 36" (91.5
cm) in height.
Making Historic Landscapes Accessible
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Preservation Brief 32: Making Historic Properties Accessible Page 10 of 13
To successfully incorporate access into historic landscapes, the planning process is
similar to that of other historic properties. Careful research and inventory should be
undertaken to determine which materials and features convey the landscape's historical
significance. As part of this evaluation, those features that are character-defining
(topographical variation, vegetation, circulation, structures, furnishings, objects) should
be identified. Historic finishes, details, and materials that also contribute to a
landscape's significance should also be documented and evaluated prior to determining
an approach to landscape accessibility. For example, aspects of the pedestrian
circulation system that need to be understood include walk width, aggregate size,
pavement pattern, texture, relief, and joint details. The context of the walk should be
understood including its edges and surrounding area. Modifications to surface textures
or widths of pathways can often be made with minimal effect on significant landscape
features.
Additionally, areas of secondary importance such as altered paths should be identified-
especially those where the accessibility modifications will not destroy a landscape's
significance. By identifying those features that are contributing or non-contributing, a
sympathetic circulation experience can then be developed.
After assessing a landscape's integrity, accessibility solutions can be considered. Full
access throughout a historic landscape may not always be possible. Generally, it is
easier to provide accessibility to larger, more open sites where there is a greater variety
of public experiences. However, when a landscape is uniformly steep, it may only be
possible to make discrete portions of a historic landscape accessible, and viewers may
only be able to experience the landscape from selected vantage points along a
prescribed pedestrian or vehicular access route. When defining such a route, the
interpretive value of the user experience should be considered; in other words, does the
route provide physical or visual access to those areas that are critical to understand the
meaning of the landscape?
Considering a New Addition as an Accessibility Solution
Many new additions are constructed specifically to incorporate modern amenities such as
elevators, restrooms, fire stairs, and new mechanical equipment. These new additions
often create opportunities to incorporate access for people with disabilities. It may be
possible, for example, to create an accessible entrance, path to public levels via a ramp,
lift, or elevator. However, a new addition has the potential to change a historic
property's appearance and destroy significant building and landscape features. Thus, all
new additions should be compatible with the size, scale, and proportions of historic
features and materials that characterize a property.
New additions should be carefully located to minimize connection points with the historic
building, such that if the addition were to be removed in the future, the essential form
and integrity of the building would remain intact. On the other hand, new additions
should also be conveniently located near parking that is connected to an accessible route
for people with disabilities. As new additions are incorporated, care should be taken to
protect significant landscape features and archeological resources. Finally, the design for
any new addition should be differentiated from the historic design so that the property's
evolution over time is clear. New additions frequently make it possible to increase
accessibility, while simultaneously reducing the level of change to historic features,
materials, and spaces.
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Preservation Brief 32: Making Historic Properties Accessible Page 11 of 13
•
Federal Accessibility Laws
.et, . ., s Today, few building owners are exempt from providing
accessibility for people with disabilities. Before making
I any accessibility modification, it is imperative to
a: $ t `` I determine which laws and codes are applicable. In
q "- y: -, a addition to local and State accessibility codes, the
% z - I following federal accessibility laws are currently in effect:
t
:7 _ ' Architectural Barriers Act (1968)
yi "Ny` t y F-.. p 0
i """"'i' 1 The Architectural Barriers Act stipulates that all buildings
x designed, constructed, and altered by the Federal
i Government, or with federal assistance, must be
=4' '1 _ accessible. Changes made to federal buildings must meet
, y.i the Uniform Federal Accessibility Standards (UFAS).
4 ! ���' r� Special provisions are included in UFAS for historic
/ • �`
buildings that would be threatened or destroyed by
y , meeting full accessibility requirements.
The automatic door to this
museum building is a practical Rehabilitation Act (1973)
solution for universal entry.
Photo: NPS files.
The Rehabilitation Act requires recipients of federal
financial assistance to make their programs and activities accessible to everyone.
Recipients are allowed to make their properties accessible by altering their building, by
moving programs and activities to accessible spaces, or by making other
accommodations.
Americans with Disabilities Act (1990)
Historic properties are not exempt from the Americans with Disabilities Act (ADA)
requirements. To the greatest extent possible, historic buildings must be as accessible
as non-historic buildings. However, it may not be possible for some historic properties to
meet the general accessibility requirements.
Under Title II of the ADA, State and local governments must remove accessibility
barriers either by shifting services and programs to accessible buildings, or by making
alterations to existing buildings. For instance, a licensing office may be moved from a
second floor to an accessible first floor space, or if this is not feasible, a mail service
might be provided. However, State and local government facilities that have historic
preservation as their main purpose-State-owned historic museums, historic State
capitols that offer tours-must give priority to physical accessibility.
Under Title III of the ADA, owners of "public accommodations" (theaters, restaurants,
retail shops, private museums) must make "readily achievable" changes; that is,
changes that can be easily accomplished without much expense. This might mean
installing a ramp, creating accessible parking, adding grab bars in bathrooms, or
modifying door hardware. The requirement to remove barriers when it is "readily
achievable" is an ongoing responsibility. When alterations, including restoration and
rehabilitation work, are made, specific accessibility requirements are triggered.
Recognizing the national interest in preserving historic properties, Congress established
alternative requirements for properties that cannot be made accessible without
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Preservation Brief 32: Making Historic Properties Accessible Page 12 of 13
"threatening or destroying" their significance. A consultation process is outlined in the
ADA's Accessibility Guidelines for owners of historic properties who believe that making
specific accessibility modifications would "threaten or destroy" the significance of their
property. In these situations, after consulting with persons with disabilities and disability
organizations, building owners should contact the State Historic Preservation Officer
(SHPO) to determine if the special accessibility provisions for historic properties may be
used. Further, if it is determined in consultation with the SHPO that compliance with the
minimum requirements would also 'threaten or destroy" the significance of the property,
alternative methods of access, such as home delivery and audio-visual programs, may
be used.
Conclusion
Historic properties are irreplaceable and require special care to ensure their preservation
for future generations. With the passage of the Americans with Disabilities Act, access to
historic properties open to the public is a now civil right, and owners of historic
properties must evaluate existing
buildings and determine how they can be made more accessible. It is a challenge to
evaluate properties thoroughly, to identify the applicable accessibility requirements, to
explore alternatives and to implement solutions that provide independent access and are
consistent with accepted historic preservation standards. Solutions for accessibility
should not destroy a property's
significant materials, features and spaces, but should increase accessibility as much as
possible. Most historic buildings are not exempt from providing accessibility, and with
careful planning, historic properties can be made more accessible, so that all citizens can
enjoy our Nation's diverse heritage.
Additional Reading
Ballantyne, Duncan S. and Harold Russell Associates, Inc. Accommodation of Disabled
Visitors at Historic Sites in the National Park System. Washington, D.C.: Park Historic
Architecture Division, National Park Service, U.S. Department of the Interior, 1983.
Goldman, Nancy. Ed. Readily Achievable Checklist: A Survey for Accessibility. Boston:
Adaptive Environments Center, 1993.
Hayward, Judith L. and Thomas C. Jester, compilers. Accessibility and Historic
Preservation Resource Guide. Windsor, Vermont: Historic Windsor, Inc., 1992, revised
1993.
Jester, Thomas C. Preserving the Past and Making it Accessible for People with
Disabilities. Washington, D.C.: Preservation Assistance Division, National Park Service,
U.S. Department of the Interior, 1992.
Parrott, Charles. Access to Historic Buildings for the Disabled. Washington, D.C.: U.S.
Department of the Interior, 1980.
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Preservation Brief 32: Making Historic Properties Accessible Page 13 of 13
Secretary of the Interior's Standards for the Treatment of Historic Properties.
Washington, D.C.: Preservation Assistance Division, National Park Service, U.S.
Department of the Interior, 1993.
Smith, William D. and Tara Goodwin Frier. Access to History: A Guide to Providing
Access to Historic Buildings for People with Disabilities. Boston: Massachusetts Historical
Commission, 1989.
Standards for Accessible Design: ADA Accessibility Guidelines (ADAAG). Washington,
D.C.: U.S. Department of Justice, 1991.
Acknowledgements
Thomas C.Jester is an Architectural Historian with the Preservation Assistance Division of the National Park Service.
Sharon C. Park,AIA, is the Senior Historical Architect with the Preservation Assistance Division, National Park
Service.
The authors wish to thank Charles A. Birnbaum,ASLA, Historical Landscape Architect with the Preservation
Assistance Division, National Park Service,for contributing the section on historic landscapes.The authors gratefully
acknowledge the invaluable comments made by the following individuals who reviewed the draft manuscript: William
Smith, Massachusetts Historical Commission; Kay Weeks, H. Ward Jandl, Michael Auer,and Charles A. Birnbaum,
Preservation Assistance Division, National Park Service; Clare Adams, New York Department of Parks, Recreation and
Historic Preservation; Lauren Bowlin, Maryland Historical Trust;Tom Mayes, National Trust for Historic Preservation;
Elizabeth Igleheart, Maine Historic Preservation Commission; Milford Wayne Donaldson, FAIA; Paul Beatty, U.S.
Architectural and Transportation Barriers Compliance Board; Mid-Atlantic Regional Office, National Park Service;
Western Regional Office, National Park Service.
Washington, D.C.September, 1993
Home page logo:Accessible historic building. Photo: NPS files.
This publication has been prepared pursuant to the National Historic Preservation Act of
1966, as amended, which directs the Secretary of the Interior to develop and make
available information concerning historic properties. Technical Preservation Services
(TPS), Heritage Preservation Services Division, National Park Service prepares
standards, guidelines, and other educational materials on responsible historic
preservation treatments for a broad public.
Order Brief I Technical Preservation Services I Preservation Briefs I Search I Questions/Answers
KDW
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Preservation Brief 35: Understanding Old Buildings: The Process of Architectural Investi... Page 1 of 13
Technical Preservation Services * "'�
"
Preservation Briefs National Park Service
U.S.Department of the interior
Understanding Old Buildings
The Process of Architectural jj %dr
Investigation 4
.r
}
Travis C. McDonald, Jr. ,•r�
•
»Determining the Purpose of Investigation
»Investigators and Investigative Skills
»Studying the Fabric of the Historic Building
»Looking More Closely
»Conducting the Architectural Investigation
»After Weighing the Evidence
»Keeping a Responsible Record
»Conclusion
»Bibliography
A NOTE TO OUR USERS:The web versions of the Preservation Briefs differ somewhat from the printed versions.
Many illustrations are new, captions are simplified, illustrations are typically in color rather than black and white, and
some complex charts have been omitted.
If you have ever felt a sense of excitement and mystery going inside an old
building--whether occupied or vacant--it is probably because its materials and features
resonate with the spirit of past people and events. Yet excitement about the unknown is
heightened when a historic structure is examined architecturally, and its evolution over
time emerges with increasing clarity to reveal the lives of its occupants. Architectural
investigation is the critical first step in planning an appropriate treatment-understanding
how a building has changed over time and assessing levels of deterioration.
Whether as a home owner making sympathetic repairs, a craftsman or contractor
replacing damaged or missing features, or a conservator reconstituting wood or
restoring decorative finishes, some type of investigative skill was used to recognize and
solve an architectural question or explain a difficult aspect of the work itself.
To date, very little has been written for the layman on the subject of architectural
investigation. This Preservation Brief thus addresses the often complex investigative
process in broad, easy-to-understand terminology. The logical sequence of planning,
investigation and analysis presented in this Brief is applicable to all buildings, geographic
locations, periods, and construction types. It is neither a "how to" nor an exhaustive
study on techniques or methodologies; rather, it serves to underscore the need for
meticulous planning prior to work on our irreplaceable cultural resources.
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Preservation Brief 35: Understanding Old Buildings: The Process of Architectural Investi... Page 2 of 13
Determining the Purpose of Investigation
Both the purpose and scope of investigation need to be determined before formulating a
particular approach. For example, investigation strictly for research purposes could
produce information for an architectural survey or for an historic designation application
at the local, state or national level.
Within the framework of The Secretary of the Interior's Standards for the
Treatment of Historic Properties, investigation is crucial for "identifying, retaining,
and preserving the form and detailing of those architectural materials and features that
are important in defining the historic character" of a property, whether for repair or
replacement. A rehabilitation project, for instance, might require an investigation to
determine the historic configuration of interior spaces prior to partitioning a room to
meet a compatible new use. Investigation for preservation work can entail more detailed
information about an entire building, such as determining the physical sequence of
construction to aid in interpretation. Investigation for a restoration project must be even
more comprehensive in order to re-capture the exact form, features, finishes, and
detailing of every component of the building.
Whether investigation will be undertaken by professionals-architects, conservators,
historians-or by interested homeowners, the process is essentially comprised of a
preliminary four-step procedure: historical research, documentation, inventory, and
stabilization.
Historical Research. Primary historical research of an old building generally
encompasses written, visual and oral resources that can provide valuable site-specific
information. Written resources usually include letters, legal transactions, account books,
insurance policies, institutional papers, and diaries. Visual resources consist of drawings,
maps, plats, paintings and photographs. Oral resources are people's remembrances of
the past. Secondary resources, comprised of research or history already compiled and
written about a subject, are also important for providing a broad contextual setting for a
project.
Historical research should be conducted well in advance of physical investigation. This
allows time for important written, visual, and oral information to be located, transcribed,
organized, studied and used for planning the actual work.
A thorough scholarly study of a building's history
--r �°" t provides a responsible framework for the physical
'1� f it 4„, x investigation; in fact, the importance of the link
'P/tt!/1fri T it i40 .ttkra=`: between written historical research and structural
/1/ff(/(l 7 ,,,,R pit,.i visa", , investigation cannot be overestimated. For
"r All.tt#�t '"ivt�
� r~1�Mt. 0 ,. example, the historical research of a building
"4°,,;.w .0 4 11 0, through deed records may merely determine the
T/i 47:4": ( ,I ,.r - sequence of owners. This, in turn, aids the
/ R4 j a ,,`� 'i investigation of the building by establishing a
--_, *re, l tt h 1,., - chronology and identifying the changes each
An inventory of animal nests found within
occupant made to the building. A letter may
hidden spaces may yield unexpected indicate that an occupant painted the building in a
evidence about food,decorative arts,and certain year; the courthouse files contain the
cultural or social traditions of everyday occupant's name; paint analysis of the building
life. Photo:Travis C. McDonald,Jr. will yield the actual color. Two-dimensional
documentary research and three-dimensional physical investigation go hand-in-hand in
analyzing historic structures. The quality and success of any restoration project is
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Preservation Brief 35:Understanding Old Buildings: The Process of Architectural Investi... Page 3 of 13
founded upon the initial research.
Documentation. A building should be documented prior to any inventory, stabilization
or investigative work in order to record crucial material evidence. A simple,
comprehensive method is to take 35 mm photographs of every wall elevation (interior
and exterior), as well as general views, and typical and unusual details. The systematic
numbering of rooms, windows and doors on the floor plan will help organize this task
and also be useful for labeling the photographs. Video coverage with annotated sound
may supplement still photographs. Additional methods of documentation include written
descriptions, sketches, and measured drawings.
Significant structures, such as individually listed National Register properties or National
Historic Landmarks, benefit from professional photographic documentation and accurate
measured drawings. Professionals frequently use The Secretary of the Interior's
Standards and Guidelines for Architectural and Engineering Documentation:
HABS/HAER Standards. It should be remembered that the documents created during
investigation might play an unforeseen role in future treatment and interpretation.
Documentation is particularly valuable when a feature will be removed or altered.
Inventory. The historic building and its components should be carefully inventoried
prior to taking any action; premature clean-up of a structure or site can be a mistake. A
careful look at all spaces in and around a building may reveal loose architectural
artifacts, fragile evidence or clues to historic landscape features. This thorough
observation includes materials and features which have fallen off due to deterioration,
fragments removed and stored in basements, attics or outbuildings, and even materials
which have seemingly been discarded.
In the beginning, anything that seems even remotely meaningful should be saved. A
common mistake is to presume to know the value of artifacts or features at the
beginning of a project. Even if the period of significance or interpretation is known from
the beginning, evidence from all periods should be protected. Documentation for future
study or use includes labeling and, if possible, photographing prior to storage in a secure
place.
Stabilization. In many cases, emergency stabilization is necessary to ensure that a
structure does not continue to deteriorate prior to a final treatment or to ensure the
safety of current occupants, investigators, or visitors. Although severe cases might call
for structural remedies, in more common situations, preliminary stabilization would be
undertaken on a maintenance level. Such work could involve installing a temporary roof
covering to keep water out; diverting water away from foundation walls; removing
plants that hold water too close to the walls; or securing a structure against intruding
insects, animals and vandals.
An old building may require temporary remedial work on exterior surfaces such as
reversible caulking or an impermanent, distinguishable mortar. Or if paint analysis is
contemplated in the future, deteriorated paint can be protected without heavy scraping
by applying a recognizable "memory" layer over all the historic layers. Stabilization adds
to the cost of any project, but human safety and the protection of historical evidence are
well worth the extra money.
Investigators and Investigative Skills
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J
General and Specialized Skills. The essential
• skill needed for any level of investigation is the
4' r ability to observe closely and to analyze. These
,,"`' M qualities are ideally combined with a hands-on
I
/ � familiarity of historic buildings-and an open
I , ' mind! Next, whether acquired in a university or
,fie p. , in a practical setting, an investigator should
, have a good general knowledge of history,
building design history and, most important,
understand both construction and finish
rt technologies.
Sri.
An investigator must have the skill and But it is not enough to know architectural style
ability to closely observe and analyze the and building technology from a national
materials with a broad understanding of viewpoint; the investigator needs to understand
historic construction practices and
technologies. Photo:Travis C. McDonald,Jr. regional and local differences as well.
While investigative skills are transferable between regions and chronological periods,
investigators must be familiar with the peculiarities of any given building type and
geographical area.
Architectural survey and comparative fieldwork provides a
crucial database for studying regional variations in historic , 2'
buildings. For example, construction practices can reflect shared
experiences of widely diverse backgrounds and traditions within
a small geographical area. Contemporary construction practice ..„. Rs:
in an urban area might vary dramatically from that of rural # -, x°``" r
areas in the same region. Neighbors or builders within the same t 4.. i LL . .
small geographical area often practice different techniques of '• *`1. Z.
constructing similar types of structures contemporaneously. .,, igi ..`W 2.;,E •
Reliable dating clues for a certain brick bond used in one state el
might be unreliable for the same period in a different state. w, i ..
Regional variation holds true for building materials as well as _.
construction.
Finally, even beyond regional and local variation, an investigator Investigation frequently
needs to understand that each building has its own unique identifies urgent needs of
history of construction and change over time. Form, features, stabilization.
materials and detailing often varied according to the tastes and Supsuch pl asementaltem supportporary ,
finances of both builder and supplier; construction quality and shoring, may be required
design were also inconsistent, as they are today. to prevent collapse.
Photo:Travis C.
McDonald,Jr.
Specialists on a Team. Because architectural investigation
requires a wide range of knowledge and many different skills, various people are likely
to interact on the same project. While homeowners frequently execute small-scale
projects, more complex projects might be directed by a craftsman, an architect or a
conservator. For large-scale projects, a team approach may need to be adopted,
consisting of professionals interacting with additional consultants. Consulting specialists
may include architectural historians, architectural conservators, craftsmen, historic finish
analysts, historians, archeologists, architects, curators, and many others. The scope and
needs of a specific project dictate the skills of key players.
Architectural investigation often includes the related fields of landscape and
archeological investigation. Landscape survey or analysis by horticulturists and
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landscape architects identify pre-existing features or plantings or those designed as
separate or complementary parts of the site. Both above and below-ground archeology
contribute information about missing or altered buildings, construction techniques,
evidence of lifestyle and material culture, and about the evolution of the historic
landscape itself.
Architectural Evidence: Studying the Fabric of the Historic
Building:
Original Construction and Later Changes. Research prior to investigation may have
indicated the architect, builder or a building's date of construction. In the absence of
such information, architectural histories and field guides to architectural style can help
identify a structure's age through its form and style.
Any preliminary date, however, has to be corroborated with other physical or
documentary facts. Dates given for stylistic periods are general and tend to be
somewhat arbitrary, with numerous local variations. Overall form and style can also be
misleading due to subsequent additions and alterations. When the basic form seems in
conflict with the details, it may indicate a transition between styles or that a style was
simply upgraded through new work.
The architectural investigation usually determines original construction details, the
chronology of later alterations, and the physical condition of a structure. Most structures
over fifty years old have been altered, even if only by natural forces. People living in a
house or using a building for any length of time leave some physical record of their time
there, however subtle.
A longer period of occupancy generally counts for greater physical change. Buildings
acquire a "historic character" as changes are made over time.
Changes to architectural form over time are generally attributable to material durability,
improvement in convenience systems, and aesthetics. First, the durability of building
materials is affected by weathering, temperature and humidity, by disasters such as
storms, floods or fire, or by air pollution from automobiles and industry. Second,
changes in architectural form have always been made for convenience' sake-fueled by
technological innovations-as people embrace better lighting, plumbing, heating,
sanitation, and communication. People alter living spaces to meet changing family
needs. Finally, people make changes to architectural form, features, and detailing to
conform to current taste and style.
Looking More Closely at Historic Building Materials and
Features
Although brick or wood frame buildings are the most common in this country, similar
sets of characteristics and questions can be established for examining log, adobe, steel,
or any other material.
Masonry. Studying historic brickwork can
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provide important information about methods
of production and construction. For example,
_ the color, size, shape and texture of brick
reveals whether it was hand molded and
traditionally fired in a clamp with hardwoods,
or whether it was machine molded and fired in
; ' a kiln usingmodern fuels. Similar) the
i #er e Y�
Ar'" �� «= principal component part of masonry mortar,
MattNialitiletifin the lime or cement, reveals whether it was
47.:7 rstr.v, Ma produced in a traditional or modern manner.
kd.4 ± I ' Y 4y Certain questions need to be asked during
Z ".;,r; F ,. 'tiw investigation. Is the mortar made with a
Careful examination of the masonry reveals natural or a Portland cement? If a natural
different periods of construction and repair cement, did it come from an oyster shell or a
through the composition and detailing of
bricks and mortar. Depending on location, limestone source? Is it hydrated or hydraulic?
the vertical open joints may indicate the As a construction unit, brick and mortar further
location of nailing blocks for decorative trim reveal something about the time, place and
McDonald,or weeps Jr.or drainage. Photo:Travis C.
human variables of construction, such as the
type of bond, special brick shapes, decorative
uses of glazed or rubbed brick, coatings and finishes, and different joints, striking and
tooling. Does the bond conform with neighboring or regional buildings of the same
period? Does the pattern of "make up" bricks in a Flemish Bond indicate the number of
different bricklayers? What is the method of attaching wood trim to the masonry?
The same types of questions related to production and construction characteristics can
be applied to all types of masonry work, including stone, concrete, terra cotta, adobe
and coquina construction. A complete survey undertaken during "surface mapping" can
outline the materials and construction practices for the various periods of a structure,
distinguishing the original work as well as the additions, alterations, and replacements.
Wood. Buildings constructed with wood have a very different
set of characteristics, requiring a different line of questioning.
Is the wooden structural system log, timber frame, or balloon
frame construction? Evidence seen on the wood surface
indicates whether production was by ax, adze, pit saw, mill saw
(sash or circular), or band saw. What are the varying ,
dimensions of the lumber used? Finished parts can be sawn, _ erg-
carved, or planed (byhand orb machine). Were
gouged, Ythey a.;
fastened by notching, mortise and tenon, pegs, or nailing? If 71.
nails were used, were they wrought by hand, machine cut with
wrought heads, entirely machine cut, or machine wire nails? For
much of the nineteenth century the manufacture of nails .
underwent a series of changes and improvements that are
dateable, allowing nails to be used as a tool in establishing
periods of construction and alteration. Regardless of region or Analyzing the nail
era, the method of framing, joining and finishing a wooden technology can help
structure will divulge something about the original construction, d
constructionestablishthe andperio provofide
its alterations, and the practices of its builders. Finally, does other important
some of the wood appear to be re-used or re-cycled? Re-used information. Photo:Travis
and reproduction materials used in early restoration projects C. McDonald,Jr.
have confused many investigators. When no identification record was kept, it can be a
problem distinguishing between materials original to the house and later replacement
materials.
Roofs. Exterior features are especially prone to
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alteration due to weathering and lack of
tr N = maintenance. Even in the best preserved
structures, the exterior often consists of replaced or
repaired roofing parts. Roof coverings typically last
l ' no more than fiftyyears. Are several generation of
,, „� roof coverings still in place? Can the layers be
-,'W.X.' `-- '? y identified? If earlier coverings were removed, the
-� ` . sheathing boards frequently provide clues to the
�. ,..t.,�� - type of covering as well as missing roof features.
Dormers, cupolas, finials, cresting, weathervanes,
In many cases,new materials or gutters, lightning rods, skylights, balustrades,
coverings are placed directly over parapets and platforms come and go as taste,
existing exterior features, preserving function and maintenance dictate. The roof pitch
the original materials underneath. Here,
the removal of a modern shingle roof itself can be a clue to stylistic dating and is unlikely
and its underlayment revealed an to change unless the entire roof has been rebuilt.
historic standing seam metal roof. Chimneys might hold clues to original roof pitch,
Photo: Courtesy, Phillips and Opperman,
P.A. flashings, and roof feature attachments. Is it
possible to look down a chimney and count the
number of flues? This practice has occasionally turned up a missing fireplace. In many
parts of the country, nineteenth-century roof coverings evolved from wooden shingles or
slate shingles, to metal shingles, to sheet metal, and still later in the twentieth century,
to asphaltic or asbestos shingles. Clay tiles can be found covering roofs in seventeenth
and eighteenth-century settlements of the east coast as well as western and
southwestern Spanish settlements from the same period. Beyond the mid-nineteenth
century, and into the twentieth, the range and choice of roof coverings greatly
expanded.
Floors. In addition to production and construction clues, floors reveal other information
about the interior, such as circulation patterns, furniture placement, the use of carpets,
floor cloths, and applied floor finishes. Is there a pattern of tack holes? Tacks or tack
holes often indicate the position and even the type of a floor covering. A thorough
understanding of the seasonal uses of floor coverings and the technological history of
their manufacture provide the background for identifying this type of evidence.
Walls. Walls and their associated trim, both outside
and inside, hold many clues to the building's
construction and changes made over time. The
overall style of moldings, trim and finishes, and their
•,y, y, hierarchical relationship, can help explain original
,�, >_ . -�1 construction as well as room usage and social
1 interaction between rooms. Holes, scars, patches
1 ' nails, nail holes, screws and other hardware indicate
former attachments. Are there "ghosts," or shadow
outlines of missing features, or trim attachments
i:4
s such as bases, chair rails, door and window casings,
* entablatures, cornices, mantels and shelves? Ghosts
Destructive investigation can be can be formed by paint, plaster, stucco, wear,
limited to small areas where evidence weathering or dirt. Interior walls from the eighteenth
can be predicted,such as walls being and early nineteenth-century were traditionally
re-built in a different location. Photo: plastered after grounds or finished trim was in place,
Travis C. McDonald,Jr. leaving an absence of plaster on the wall behind
them. Evidence of attachments on window casings can also be helpful in understanding
certain interior changes. Other clues to look for include the installation of re-used
material brought into a house or moved about within a house; worker's or occupant's
graffiti, especially on the back of trim; and hidden finishes or wallpaper stuck in crevices
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or underneath pieces of trim. Stylistic upgrading often resulted in the re-use of outdated
trim for blocking or shims. Unexpected discoveries are particularly rewarding.
Investigators frequently tell stories about clues that were uncovered from architectural
fragments carried off by rats and later found, or left by workers in attics, between walls
and under floors.
Attics and Basements. Attics and basements have been known as collection points for
out-of-date, out-of-style and cast-off pieces such as mechanical systems, furnishings,
family records and architectural fragments. These and other out-of-the-way places of a
structure provide an excellent opportunity for non-destructive investigation. Not only are
these areas where structural and framing members might be exposed to view, they are
also areas which may have escaped the frequent alteration campaigns that occur in the
more lived-in parts of a building. If a building has been raised or lowered in height,
evidence of change would be found in the attic as fx
well as on the exterior. Evidence of additions .
might also be detected in both the attic and the
basement. Attics frequently provide a "top-side"
view at the ceiling below, revealing its material, --�
manner of production and method of attachment. �� 7
A "bottom-side" view of the roof sheathing or roof } - *.
covering can be seen from the attic as well
Basements generally relate more to human
service functions in earlier buildings and to i
N
mechanical services in more recent eras. For ,
example, a cellar of an urban 1812 house Discarded items are routinely stored
disclosed the following information during an within attics,then forgotten only to be
investigation: first period bell system, discovered during a later investigation.
Sidentification of a servant's hall, hidden fireplace, answer
manyly worthless debris. may help
p � answer questions. Photo:Travis C.
displacement of the service stairs, McDonald,Jr.
identification of a servants' quarters, an 1850s furnace system, 1850s gas and plumbing
systems, relocation of the kitchen in 1870, early use of 1890s concrete floor slabs and
finally, twentieth century utility systems. While the earliest era had been established as
the interpretation period, evidence from all periods was documented in order to
understand and interpret how the house evolved or changed over time.
Mechanical, Electrical, Plumbing and Other Systems. Systems of utility and
convenience bear close scrutiny during investigation. All historic buildings inhabited and
used by people reveal some association, at the very minimum, with the necessities of
lighting, climate control, water, food preparation, and waste removal. Later installations
in a building may include communication, hygiene, food storage, security, and lightning
protection systems. Other systems, such as transportation, are related to more specific
functions of commercial or public structures. Although research into the social uses of
rooms and their furnishings has borne many new studies, parallel research into how
people actually carried out the most mundane tasks of everyday life has been fairly
neglected. Utility and convenience systems are most prone to alteration and upgrading
and, at the same time, less apt to be preserved, documented or re-used. Understanding
the history or use of a building, and the history of systems technology can help predict
the physical evidence that might be found, and what it will look like after it is found.
Conducting the Architectural Investigation
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Architectural investigation can range from a simple one hour walk-through to a month
long or even multi-year project-and varies from looking at surfaces to professional sub-
surface examination and laboratory work.
All projects should begin with the simplest, non-destructive processes and proceed as
necessary. The sequence of investigation starts with reconnaissance and progresses to
surface examination and mapping, sub-surface non-destructive testing, and various
degrees of sub-surface destructive testing.
Reconnaissance. An initial reconnaissance trip through a structure-or visual overview-
provides the most limited type of investigation. But experienced investigators
accustomed to observation and analysis can resolve many questions in a two-to-four
hour preliminary site visit. They may be able to determine the consistency of the
building's original form and details as well as major changes made over time.
Surface Mapping. The first step in a thorough, systematic
investigation is the examination of all surfaces. Surface
investigation is sometimes called "surface mapping"
g Aping since it
entails a minute look at all the exterior and interior surfaces.
The fourfold purpose of surface mapping is to observe every
„:„,o, visible detail of design and construction; develop questions
related to evidence and possible alterations; note structural or
environmental problems; and help develop plans for any further
• investigation. Following investigation, a set of documentary
'` drawings and photographs is prepared which record or "map"
the evidence.
4 While relying upon senses of sight and touch, the most useful
w 3 tool for examining surfaces is a high-powered, portable light
used for illuminating dark spaces as well as for enhancing
Raking light is used to surface subtleties. Rakinglight at an angle on a flat surface is
show irregularities on flat 9
surfaces. Patches,repairs, one of the most effective means of seeing evidence of
and alterations can then attachments, repairs or alterations.
be mapped by the
shadows or ghosts they
cast. Photo:Travis C. Non-Destructive Testing. The next level of investigation
McDonald,Jr. consists of probing beneath surfaces using non-destructive
methods. Questions derived from the surface mapping examination and analysis will
help determine which areas to probe. Investigators have perfected a number of tools
and techniques which provide minimal damage to historic fabric. These include x-rays to
penetrate surfaces in order to see nail types and joining details; boroscopes, fiber optics
and small auto mechanic or dentists' mirrors to look inside of tight spaces; and ultra
violet or infra-red lights to observe differences in materials and finishes. The most
advanced technology combines the boroscope with video cameras using fiber optic
illumination. In addition to the more common use of infra-red photography, similar non-
destructive techniques used in archeological investigations include remote sensing and
ground-penetrating radar.
Small material samples of wood, plaster, mortar, or paint can also be taken for
laboratory analysis at this stage of investigation. For instance, a surface examination of
a plaster wall using a raking light may show clear evidence of patching which
corresponds to a shelf design. Were the shelves original or a later addition? A small
sample of plaster from the patched area is analyzed in the laboratory and matches
plaster already dated to a third period of construction. A probe further reveals an
absence of first period plaster on the wall underneath. The investigator might conclude
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from this evidence that the shelves were an original feature and that the plaster fill
dates their removal and patching to a third period of construction.
Destructive Testing. Most investigations require
nothing more than historical research, surface
examination and non-destructive testing. In very r, �a
rare instances the investigation may require a
sub-surface examination and the removal of ,iiy' t
4,
y wS , F`O
fabric. Destructive testing should be carried out i to
by a professional only after historical research and t
surface mapping have been fully accomplished
and only after non-destructive testing has failed
to produce the necessary information. Owners
should be aware that the work is a form of
demolition in which the physical record may be c -
destroyed. Sub-surface examination begins with
the most accessible spaces, such as retrofitted
service and mechanical chases; loose or
previously altered trim, ceilings or floor boards; Exploratory testing was used to verify the
location of an abandoned fireplace. Plaster
and pieces of trim or hardware which can be and brick were carefully documented and
easily removed and replaced. removed to determine the fireplace's type,
size,and location. Photo:Travis C.
McDonald,Jr.
Non-destructive testing techniques do not damage
historic fabric. If non-destructive techniques are not sufficient to resolve important
questions, however, small "windows" can be opened in surface fabric at predetermined
locations to see beneath the surface. This type of subsurface testing and removal is
sometimes called "architectural archeology" because of its similarity to the more well-
known process of trenching in archeology. The analogy is apt because both forms of
archeology use a method of destructive investigation.
Photographs, video and drawings should record the before, during and after evidence
when the removal of historic fabric is necessary. The selection and sequence of material
to be removed requires careful study so that original extant fabric remains in situ if
possible. If removed, original fabric should be carefully put back or labeled and stored.
At least one documentary patch of each historic finish should be retained in situ for
future research. Treatment and interpretation, no matter how accurate, are usually not
final; treatment tends to be cyclical, like history, and documentation must be left for
future generations, both on the wall and in the files.
Laboratory Analysis. Laboratory analysis plays a scientific role in the more intuitive
process of architectural investigation. One of the most commonly known laboratory
procedures used in architectural investigation is that of historic paint analysis. The
chronology and stratigraphy of applied layers can establish appropriate colors, finishes,
designs or wall coverings. When conducted simultaneously with architectural
investigation, the stratigraphy of finishes, like that of stratigraphic soils in archeology,
helps determine the sequence of construction or alterations in a building. Preliminary
findings from in situ examinations of painted finishes on walls or trim are common, but
more accurate results come from extensive sampling and microscopic laboratory work
using chemical analysis and standardized color notations. Consultants without the proper
knowledge have been known to cause far more harm than good.
Mortar and plaster analysis often provide a basis for dating construction with minimal
intervention. Relatively small samples of the lime-based materials can be chemically
separated into their component parts of sands and fines, which are then visually
compared to equivalent parts of known or dated samples. A more thorough scientific
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approach may be used to accurately profile and compare samples of other materials
through elemental analysis. Two similar methods in common use are Neutron Activation
and Energy Dispersive Spectroscopy (EDS). Neutron Activation identifies the sample's
trace elements by monitoring their response to neutron bombardment. EDS measures
the response to electron bombardment through the use of an electron microscope. In
both tests, the gathered information is plotted and matched with the reactions of known
elements. The results provide a quantitative and qualitative profile of the sample's
elemental components for use in further comparisons.
Dendrochronology presents a minimally destructive process for dating wooden
members. Also called tree ring dating, this process relies on the comparative wet and
dry growth seasons of trees as seen in their rings via a core sample. This technique has
two limitations: a very extensive data base must be compiled for climatic conditions over
a long span of years and matched with corresponding tree ring samples; and the core
samples can only be taken from timber which still has a bark edge. Simple identification
of wood species during an investigation can be determined from small samples sent to a
forest products laboratory.
After Architectural Investigation: Weighing the Evidence
Evidence, questions, and hypotheses must be continually evaluated during investigation.
Like a detective constructing a case, an investigator must sort out information to get at
"the facts." Yet, are the "facts" conclusive at any time?
Observations made during the surface mapping may identify random features. These
features begin to form patterns; then, sets of patterns, perhaps representing alterations
from multiple eras, begin to appear. If the right questions are not asked, the evidence
can remain hidden. Hypotheses are formed, questioned, tested, re-formed and either
rejected or substantiated. This process is repeated as more "facts" are uncovered and
questions asked. Eventually the evidence seems conclusive. These conclusions, in turn,
may lead to re-examination, more historical research, and the advice of specialized
consultants. At some point, treatment generally follows based on the collective,
educated conclusions of an entire professional team.
Keeping a Responsible Record for Future Investigators
The evidence collected during investigation, and any conclusions which can be drawn
from it, should be documented in a written report. The complexity of a project dictates
the complexity of the resulting record. It may be wise to maintain a report in an
expandable format if long or extensive work is expected-additional evidence will
undoubtedly need to be incorporated that alters previous conclusions. Reports tend to
range from annotated photographs in loose-leaf binders to full-length bound "books."
Putting findings and conclusions in an accessible form helps those who are planning
treatment. For example, a rehabilitation project may require documentation to satisfy
grant funding or tax credit program requirements; preservation and restoration projects
always need careful documentation to guide the work. After work, the investigation
report and notes on the treatment itself are made into a permanent file record. Whether
or not work is being planned, the architectural investigation report will always be of
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ti.
value to future researchers or owners of the building.
The most common professional document is called an Historic Structure Report. This
invaluable tool for preservation typically contains historical as well as physical
information. Sections include a history of the building, an architectural description of the
original structure and changes made over time, the results of all investigations, a record
of current conditions or problems, of past repairs and treatments, and recommendations
for current and future action. They are seldom definitive; thus, research is a continuing
process.
Conclusion
Architectural investigation plays a critical role in making responsible decisions about
treating and interpreting historic buildings. A successful project to research, inventory,
document, and ultimately treat and interpret a building is directly linked to the
knowledge and skills of
architectural investigators and other historic preservation specialists. The expressed goal
of historic preservation is to protect and preserve materials and features that convey the
significant history of a place. Careful architectural investigation-together with historical
research-provides a firm foundation for this goal.
Bibliography
Bullock, Orin M. Jr., The Restoration Manual. Norwalk, CT.: Silvermine Publishers, 1966.
Burns, John A., editor. Recording Historic Structures. Washington, D.C.: The AIA Press,
1989.
Hdward, Hugh. How Old Is This House?. New York: Noonday Press, 1989.
Howe, Barbara J., Dolores A. Fleming, Emory L. Kemp, and Ruth Ann Overbeck. Houses
and Homes: Exploring Their History. Nashville, TN.: American Association for State and
Local History, 1987.
Judd, Henry A., Before Restoration Begins. Nashville, TN.: American Association for
State and Local History, 1973.
Kitchen, Judith L., Caring For Your Old House. Washington, D.C.: The Preservation Press,
1991.
Seale, William, Recreating the Historic House Interior. Nashville, TN.: American
Association for State and Local History, 1979.
Secretary of the Interior's Standards for the Treatment of Historic Properties.
Washington, D.C.: Preservation Assistance Division, National Park Service, U.S.
Department of the Interior, 1992.
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Secretary of the Interior's Standards and Guidelines for Architectural and Engineering
Documentation: HABS/HAER Standards. Washington, D.C.: HABS/HAER, National Park
Service, U.S. Department of the Interior, 1990.
Acknowledgements
Travis C.McDonald,Jr., is an architectural historian who serves as the Director of Architectural Restoration at
Thomas Jefferson's Poplar Forest near Lynchburg,Virginia. He respectively dedicates this work to three masters of
architectural investigation: Henry A.Judd,former Chief Historical Architect of the National Park Service; Lee H.
Nelson, former Chief, Preservation Assistance Division NPS; and Paul E. Buchanan,former Director of Architectural
Research at the Colonial Williamsburg Foundation.The author gratefully acknowledges the following professionals for
their help in reviewing this manuscript: Edward A. Chappell, Colonial Williamsburg; E. Blaine Cliver, Preservation
Assistance Division NPS; Stanley O. Graves, National Conference of State Historic Preservation Officers; Bernard L.
Herman, University of Delaware; H. Ward Jandl, Preservation Assistance Division NPS; Hugh C. Miller,Virginia State
Historic Preservation Office; Orlando Ridout V, Maryland Historical Trust; William Seale; and professional staff
members of the National Park Service.Timothy A. Buehner served as project coordinator and Kay D.
Weeksserved as project editor.
Washington,D.C. September, 1994
Home page logo: Architectural investigator at work. Photo: Courtesy,Valentine Museum.
This publication has been prepared pursuant to the National Historic Preservation Act of
1966, as amended, which directs the Secretary of the Interior to develop and make
available information concerning historic properties. Technical Preservation Services
(TPS), Heritage Preservation Services Division, National Park Service prepares
standards, guidelines, and other educational materials on responsible historic
preservation treatments for a broad public.
Order Brief I Technical Preservation Services I Preservation Briefs I Search I Questions/Answers
KDW
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