Detail of restored roof; Link to Parknet
STANDARDS FOR RESTORATION AND GUIDELINES FOR RESTORING HISTORIC BUILDINGS
<photo> historic wood elements

Identify    Protect    Repair    Replace    Remove   Re-Create

Identify, Retain and Preserve

Recommend
Identifying, retaining, and preserving wood features from the restoration period such as siding, cornices, brackets, window architraves, and doorway pediments; and their paints, finishes, and color.

photo of the 19th century stick-style Emlen Physick House in Cape May, NJ


The form, features, and detailing of this 19th century stick-style villa (The Emlen Physick House in Cape May, New Jersey) have been retained and preserved. The National Historic Landmark structure is open to the public. Photo: HABS Collection, NPS.

Not Recommended
Altering wood features from the restoration period.

Failing to properly document wood features from the restoration period which may result in their loss.

Applying paint or other coatings to wood or removing paint from wood if such treatments cannot be documented to the restoration period.

Changing the type or color of the paint or coating unless the work can be substantiated by historical documentation.

Protect and Maintain

Recommend
Protecting and maintaining wood features from the restoration period by providing proper drainage so that water is not allowed to stand on flat, horizontal surfaces or accumulate in decorative features.

photo of broken downspout that needs to be repaired to prevent serious moisture problems

Repair of this broken downspout is essential to prevent damage to the historic building as well as to prevent serious moisture problems in below-grade foundation walls and the basement. Photo: NPS files.

Applying chemical preservatives to wood features such as beam ends or outriggers that are exposed to decay hazards and are traditionally unpainted.

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.

Inspecting painted wood surfaces to determine whether repainting is necessary or if cleaning is all that is required.

Removing damaged or deteriorated paint to the next sound layer using the gentlest method possible (handscraping and handsanding), then repainting.

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 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.Applying compatible paint coating systems following proper surface preparation.

Repainting with colors that are documented to the restoration period of the building.

Evaluating the existing condition of the wood to determine whether more than protection and maintenance are required, that is, if repairs to wood features from the restoration period will be necessary.

Not Recommended
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.

Using chemical preservatives such as creosote which, unless they were used historically, can change the appearance of wood features.

Stripping paint or other coatings to reveal bare wood, thus exposing historically coated surfaces to the effects of accelerated weathering.

Removing paint that is firmly adhering to, and thus, protecting wood surfaces.

Using destructive paint removal methods such as propane or butane torches, sandblasting or waterblasting. These methods can irreversibly damage historic woodwork.

Using thermal devices improperly so that the historic woodwork is scorched.

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 surface roughened.

Failing to follow manufacturers' product and application instructions when repainting exterior woodwork.

Using new colors that are not documented to the restoration period of the building.

Failing to undertake adequate measures to assure the protection of wood features from the restoration period.

Repair

Recommend
Repairing, stabilizing, and conserving fragile wood from the restoration period using well-tested consolidants, when appropriate. Repairs should be physically and visually compatible and identifiable upon close inspection for future research.

photos showing restoration of historic totem pole at Sitka National Historical Park, AK

The totem pole collection at Sitka National Historical Park (top) embodies the rich carving traditions--past and present--of Southeast Alaskan Natives. In a project to restore the carvings along one pole to reduce water penetration and fungal decay, borates were first applied (left) using a sprayer and brushes; and (right) a water-repellent with mildewcide was applied. Photos: NPS files.

Repairing wood features from the restoration period by patching, piecing-in, 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 from the restoration period where there are surviving prototypes such as brackets, molding, or sections of siding. The new work should be unobtrusively dated to guide future research and treatment.

Not Recommended
Removing wood from the restoration period that could be stabilized and conserved; or using untested consolidants and untrained personnel, thus causing further damage to fragile historic materials.

Replacing an entire wood feature from the restoration period such as a cornice or wall when repair of the wood and limited replacement of deteriorated or missing parts are appropriate.

Using substitute material for the replacement part that does not convey the visual appearance of the surviving parts of the wood feature or that is physically or chemically incompatible.

Replace

Recommend
Replacing in kind an entire wood feature from the restoration period that is too deteriorated to repair--if the overall form and detailing are still evident--using the physical evidence as a model to reproduce the feature. 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. The new work should be unobtrusively dated to guide future research and treatment.

Not Recommended
Removing a wood feature from the restoration period that is unrepairable and not replacing it.

The following Restoration work is highlighted to indicate that it involves the removal or alteration of existing historic wood features that would be retained in Preservation and Rehabilitation treatments; and the replacement of missing wood features from the restoration period using all new materials.

Removing Existing Features from Other Historic Periods

Recommend
Removing or altering wood features from other historic periods such as a later doorway, porch, or steps.

photo showing removal of later wood siding to restore the original appearance of a 19th century house

19th century clapboards and trim have been discovered underneath mid-20th century shingles. All the later shingles will be removed in order to restore the original appearance of the house. The consistent backdating of a historic building is a major documentary effort that goes far beyond the ordinary maintenance of existing materials and features. Photo: © John Leeke.

Documenting materials and features dating from other periods prior to their alteration or removal. If possible, selected examples of these features or materials should be stored to facilitate future research.

Not Recommended
Failing to remove a wood feature from another period, thus confusing the depiction of the building's significance.Failing to document wood features from other historic periods that are removed from the building so that a valuable portion of the historic record is lost.

Re-creating Missing Features from the Restoration Period

Recommend
Re-creating a missing wood feature that existed during the restoration period based on physical or documentary evidence; for example, duplicating a roof dormer or porch.

Not Recommended

Constructing a wood feature that was part of the original design for the building, but was never actually built; or constructing a feature which was thought to have existed during the restoration period, but for which there is insufficient documentation.

 

-GUIDELINES-

The Approach

Exterior Materials
Masonry
Wood
Architectural Metals

Exterior Features
Roofs
Windows
Entrances + Porches
Storefronts

Interior Features
Structural System Spaces/Features/Finishes
Mechanical Systems

Site

Setting

Special Requirements
Energy Efficiency
Accessibility
Health + Safety

The Standards

 

  HISTORICAL OVERVIEW - PRESERVING - REHABILITATING - restoring- RECONSTRUCTING

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Historical Overview