Historic Preservation - Technical Procedures
Guidelines For Rehabilitating Historic Buildings: Wood
National Park Service, Preservation Assistance Division
Guidelines For Rehabilitating Historic Buildings: Wood
GUIDELINES FOR REHABILITATING HISTORIC BUILDINGS: WOOD
U.S. Department of the Interior
National Park Service
Preservation Assistance Division
An illustrated booklet addressing the Secretary's Standards and the
guidelines is available from the U.S. Government Printing Office.
The title is "The Secretary of the Interior's Standards for
Rehabilitation & Illustrated Guidelines for Rehabilitating Historic
Buildings", ISBN 0-16-035979-1.
Each of the guidelines included in the booklet mentioned above have
been separated into individual entries for specific use in HBPP.
This entry represents one of many guidelines included in the
booklet and describes RECOMMENDED and NOT RECOMMENDED applications
of the Secretary of the Interior's Standards as they relate to
Wood. For a list of the Secretary of the Interior's Standards for
Rehabilitation, see 01091-04-S; For general information relating to
the purpose, organization and content of the individual guidelines,
see 01091-05-S. Both of these entries should be referenced along
with the information contained in this document.
WOOD: Clapboard, weatherboard, shingles, and other wooden siding
and decorative elements
Because it can be easily shaped by sawing, planing, carving, and
gouging, wood is the most commonly used material for architectural
features such as clapboards, cornices, brackets, entablatures,
shutters, columns and balustrades. These wooden features - both
functional and decorative - may be important in defining the
historic character of the building and thus their retention,
protection, and repair are of particular importance in
IDENTIFYING, RETAINING AND PRESERVING
- Identifying, retaining, and preserving wood features that
are important in defining the overall historic character
of the building such as siding, cornices, brackets,
window architraves, and doorway pediments; and their
paints, finishes, and colors.
- Removing or radically changing wood features which are
important in defining the overall historic character of
the building so that, as a result, the character is
- Removing a major portion of the historic wood from a
facade instead of repairing or replacing only the
deteriorated wood, then reconstructing the facade with
new material in order to achieve a uniform or "improved"
- Radically changing the type of finish or its color or
accent scheme so that the historic character of the
exterior is diminished.
- Stripping historically painted surfaces to bare wood,
then applying clear finishes or stains in order to create
a "natural look."
- Stripping paint or varnish to bare wood rather than
repairing or reapplying a special finish, i.e., a grained
finish to an exterior wood feature such as a front door.
PROTECTING AND MAINTAINING
- Protecting and maintaining wood features by providing
proper drainage so that water is not allowed to stand on
flat, horizontal surfaces or accumulate in decorative
- Failing to identify, evaluate, and treat the causes of
wood deterioration, including faulty flashing, leaking
gutters, cracks and holes in siding, deteriorated
caulking in joints and seams, plant material growing too
close to wood surfaces, or insect or fungus infestation.
- Applying chemical preservatives to wood features such as
beam ends or outriggers that are exposed to decay hazards
and are traditionally unpainted.
- Using chemical preservatives such as creosote which can
change the appearance of wood features unless they were
- Retaining coatings such as paint that help protect the
wood from moisture and ultraviolet light. Paint removal
should be considered only where there is paint surface
deterioration and as part of an overall maintenance
program which involves repainting or applying other
appropriate protective coatings.
- Stripping paint or other coatings to reveal bare wood,
thus exposing historically coated surfaces to the effects
of accelerated weathering.
- Inspecting painted wood surfaces to determine whether
repainting is necessary or if cleaning is all that is
- Removing paint that is firmly adhering to, and thus,
protecting wood surfaces.
- Removing damaged or deteriorated paint to the next sound
layer using the gentlest method possible (handscraping
and handsanding), then repainting.
- Using destructive paint removal methods such as propane
or butane torches, sandblasting or waterblasting. These
methods can irreversibly damage historic woodwork.
- Using with care electric hot-air guns on decorative wood
features and electric heat plates on flat wood surfaces
when paint is so deteriorated that total removal is
necessary prior to repainting.
- Using thermal devices improperly so that the historic
woodwork is scorched.
- Using chemical strippers primarily to supplement other
methods such as handscraping, handsanding and the above-
recommended thermal devices. Detachable wooden elements
such as shutters, doors, and columns may -- with the
proper safeguards -- be chemically dip-stripped.
- Failing to neutralize the wood thoroughly after using
chemicals so that new paint does not adhere.
- Allowing detachable wood features to soak too long in a
caustic solution so that the wood grain is raised and the
- Applying compatible paint coating systems following
proper surface preparation.
- Failing to follow manufacturers' product and application
instructions when repainting exterior woodwork.
- Repainting with colors that are appropriate to the
historic building and district.
- Using new colors that are inappropriate to the historic
building or district.
- Evaluating the overall condition of the wood to
determine whether more than protection and maintenance
are required, that is, if repairs to wood features will
- Failing to undertake adequate measures to assure the
preservation of wood features.
- Repairing wood features by patching, piecing-in,
consolidating, or otherwise reinforcing the wood using
recognized preservation methods. Repair may also include
the limited replacement in kind -- or with compatible
substitute material -- of those extensively deteriorated
or missing parts of features where there are surviving
prototypes such as brackets, moldings, or sections of
- Replacing an entire wood feature such as a cornice or
wall when repair of the wood and limited replacement of
deteriorated or missing parts are appropriate.
- Using substitute materials for the replacement part that
does not convey the visual appearance of the surviving
parts of the wood feature or that is physically or
- Replacing in kind an entire wood feature that is too
deteriorated to repair -- if the overall form and
detailing are still evident -- using the physical
evidence to guide the new work. Examples of wood
features include a cornice, entablature or balustrade.
If using the same kind of material is not technically or
economically feasible, then a compatible substitute
material may be considered.
- Removing an entire wood feature that is unrepairable and
not replacing it; or replacing it with a new feature that
does not convey the same visual appearance.
NOTE: THE FOLLOWING REPRESENTS PARTICULARLY COMPLEX TECHNICAL OR
DESIGN ASPECTS OF REHABILITATION PROJECTS AND SHOULD ONLY BE
CONSIDERED AFTER THE PRESERVATION CONCERNS LISTED ABOVE HAVE BEEN
DESIGN FOR MISSING HISTORIC FEATURES
- Designing and installing a new wood feature such as a
cornice or doorway when the historic features is
completely missing. It may be an accurate restoration
using historical, pictorial, and physical documentation,
or be a new design that is compatible with the size,
scale, material, and color of the historic building.
- Creating a false historic appearance because the replaced
wood feature is based on insufficient historical,
pictorial, and physical documentation.
- Introducing a new wood feature that is incompatible in
size, scale, material, and color.
END OF SECTION