Common Rehabilitation Concerns and Treatments

Some treatments to historic properties can be problematic. The Guidelines for Rehabilitating Historic Buildings accompanying the Secretary of the Interior’s Standards for Rehabilitation, as well as information available on the NPS website, provide further guidance on these and other treatments. Applicants should address these concerns when undertaking work in any of these areas and include the information outlined below in the application.

Exterior Masonry Cleaning

Applicants are strongly encouraged to clean masonry only when necessary to halt deterioration or to remove graffiti and stains. Indicate the condition of each material to be cleaned. Specify what the cleaning is intended to accomplish (soot removal, paint removal, etc.) and what process is to be used. When chemical systems are to be employed, specify the product to be used and its application. Information for cleaning involving chemical processes should include products to be used and water pressure in pounds per square inch (psi). Provide material to show that the method selected will not harm the masonry. Summarize results of test patches and include close-up color photographs of masonry surfaces before and after cleaning as evidence.

Exterior Masonry Repair

Applicants are strongly encouraged to repoint only those portions of the masonry that require repair. Indicate deteriorated areas and describe repair method proposed. Provide evidence that repointing mortar will match the historic in composition (ratio of lime, cement, sand, and any additives), color, texture, and tooling.

New Windows

Applicants are strongly encouraged to retain and repair historic windows. If replacement is proposed, indicate the condition of existing windows (sash, glazing, muntins, etc.) and the reasons for replacement. Photographs must be provided as evidence of severe deterioration; provide data on the cost of repairing existing windows versus installing replacements. Tinted glass often causes a change in character and may result in denial of certification. Where replacement of existing windows appears justified by supporting documentation, and where the windows are an integral part of the building’s design and character, replacement sash must match the original in size, pane configuration, color, trim details, and planar and reflective qualities, and, in most cases, materials. Scaled drawings comparing the existing windows with the replacement windows must be provided. See the documentation requirements for proposed window replacement on the program website.

Storefront Alterations

Applicants are strongly discouraged from introducing a storefront or new design element that alters the character of the structure and its relationship with the street or that causes destruction of significant historic material. Justify changes to storefronts and provide photographs of the areas to be altered. Document the date of construction of the existing storefront and its condition. If a historical treatment is planned, provide the evidence on which the proposed new storefront designs are based.

Interior Partitions, Trim, and Finishes

Applicants are strongly discouraged from changing historic floor plans unnecessarily and from exposing masonry surfaces unless this condition is supported by historical evidence. Document the existing condition of the interior. Indicate both historic and non-historic walls. Show walls to be removed or altered. Note whether trim and wall and ceiling finishes will be affected.

New Heating, Ventilation, and Air-Conditioning (HVAC) Systems

Indicate what effect the new equipment and ductwork will have on the historic building. New systems must not run across windows or introduce an “unfinished” character to finished interior spaces. Installation of systems that cause damage to the historic building material or visual loss of character may result in denial of certification.

New Additions and New Construction

Applicants are strongly encouraged to obtain NPS/SHPO approval before undertaking projects involving new additions or new construction. New additions may substantially alter the appearance and form of historic structures and may cause denial of certification. Similarly, new construction, including site work, may affect the relationship of a structure to its site, change the historic landscape, or otherwise damage the historic character of the property.

Applicants are strongly encouraged to submit applications and receive approval from the NPS prior to the start of work. Applicants who undertake rehabilitation projects without prior approval from the NPS do so at their own risk.