Preservation Brief #8 ~ Technical Preservation Services ~ National Park Service
| Aluminum
and Vinyl Siding on Historic Buildings |
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| The
Appropriateness of Substitute Materials for Resurfacing Historic Wood Frame
Buildings by John H. Myers, revised by Gary L. Hume |
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1. The Planning Process
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.
 Historic wood siding exhibits rich and varied surface textures. They range from hand-split clapboards of short lengths with feather-edged ends (shown here), to pit or mill sawn boards which can be beveled, rabbeted, or beaded. Photo: NPS files. |
Standard 6 of the Secretary of the Interior's Standards for Rehabilitation states that "deteriorated architectural features shall be repaired rather than replaced. Where the severity of deterioration requires replacement of a distinctive feature, the new feature shall match the old in design, color, texture, and other visual qualities and, where possible, materials..." The Guidelines further caution against "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 diminished."
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.
Acknowledgements
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.
