Technical Procedures Disclaimer
Prior to inclusion in GSA’s library of procedures, documents are reviewed by one or more qualified preservation specialists for general consistency with the Secretary of Interior Standards for rehabilitating historic buildings as understood at the time the procedure is added to the library. All specifications require project-specific editing and professional judgement regarding the applicability of a procedure to a particular building, project or location. References to products and suppliers are to serve as a general guideline and do not constitute a federal endorsement or determination that a product or method is the best or most current alternative, remains available, or is compliant with current environmental regulations and safety standards. The library of procedures is intended to serve as a resource, not a substitute, for specification development by a qualified preservation professional.
We’ve reviewed these procedures for general consistency with federal standards for rehabilitating historic buildings and provide them only as a reference. Specifications should only be applied under the guidance of a qualified preservation professional who can assess the applicability of a procedure to a particular building, project or location. References to products and suppliers serve as general guidelines and do not constitute a federal endorsement nor a determination that a product or method is the best alternative or compliant with current environmental regulations and safety standards.
This standard was adapted from a checklist developed by the National Park Service and printed in Ramsey/Sleeper's Architectural Graphic Standards.
The following checklist is intended for use in identifying some preservation factors to consider when undertaking the rehabilitation of historic buildings. Not all of the factors listed will be applicable to all structures or preservation projects.
Check Historic Designation and Available Documentation
- Is the building a local landmark or located in a locally designated historic district?
- Is it in a historic district that is listed in the National Register of Historic Places? Does it contribute to the historic significance of that district?
- Is it individually listed in the National Register of Historic Places?
- What historical or architectural documentation is available about the building(s) or site?
- National Register nominations
- Architectural or engineering drawings for construction of survey such as Historic American Buildings Survey/Historic American Engineering Record (HABS/HAER)
- State or local historical survey or inventory
- Local documents, views, photographs in libraries, archives, historical societies
Check Legal Requirements
- Are there easements or local ordinances governing alterations to property (deed records, zoning offices)?
- How do the state and local building codes apply to the historic structure?
- What impact will they have upon the character and integrity of the building?
- Are code variances available?
- Are there code equivalency possibilities for your particular building?
- Will there be federal funds involved in the project which will require review by the State Historic Preservation Office or a Section 106 compliance consultation with the Advisory Council on Historic Preservation?
- Are you familiar with the Secretary of the Interior's Standards for Rehabilitation and Guidelines for rehabilitating historic buildings?
- Have you contacted the State Historic Preservation Officer (SHPO)?
Evaluate Historic Character /Significance of the Structure
- Have you identified, listed, and prioritized the character defining aspects of the building? These may include its form, materials, workmanship, features, color, relationship of solids to voids, and interior spaces--all those physical features or tangible aspects of the building that define its historic character.
- What have been the architectural changes over time? These may include:
- new additions
- changes to surfaces and finishes (slates to asphalt, polychrome to monochrome)
- blocking of windows
- changes to grade
- loss of cornice
- false fronts
- changes to basic plan (single family to multiple family)
- Are any of the changes significant and worth preserving or do they detract from the building?
- Has the architectural integrity of the building and its setting been assessed? Architectural integrity means the intactness of the building as an architectural system (its plan, features, materials, finishes, structural system, and the presence of architectural features)
Assess Physical Condition
- Are there physical problems that threaten the building's architectural and structural integrity?
- Has a structural survey been performed to determine deficiencies due to settlement, deflection of beams, seismic inadequacy, and cuts through structural members for mechanical pipes and ducts
- Is it individually listed in the National Register of Historic Places?
- Are there inherent architectural problems, such as materials failure due to poor original design, poor original materials, severe environmental or moisture problems, neglect, improper maintenance, etc.?
- Are historic features hidden behind later alterations? (These may include ornamental ceilings or cornices hidden above dropped ceilings.)
Develop Preservation Project Plans
- Will it be necessary to write unique specifications rather than use standard specifications to apply to work performed on a historic building?
- Will testing be needed to determine the performance of the materials or the systems? Note that it may be necessary to review test results with consultants or laboratories.
- Will the project involve hard-to-find replacement materials such as terra-cotta or ornamental metals that may require logistical planning?
- Are samples or models available for use in establishing the standard of craftsmanship for the project?
- Will the project involve energy conservation measures
- Have historic materials and finishes been retained to the maximum extent possible?
- Will new uses require upgrading the loading capacity of wooden floor joists? Will the preservation objectives affect the decision making?
- For instance, it is better to double up existing joists with a parallel member than to remove historic materials, and if an ornamental ceiling would be damaged by this approach, a structural engineer should investigate other alternatives
- Has the impact of new additions and adjacent new construction been minimized by keeping the size, shape, materials, and detailing in scale with the surrounding environment?
- What protective measures will be taken to preserve important character-defining features and finishes during the construction work?
- On the exterior, will the rehabilitation work cause loss of significant historic fabric or seriously damage the historic character?
- Loss of historic fabric or change of historic character often occur when:
- storefronts and entrances are altered
- visible skylights are added to a roof
- dormers are added on prominent roofs
- new floors are added on top of an existing building
- porches are enclosed
- new window openings are created
- tinted films or reflective coatings are added to
- new window sash are historically inappropriate as to configuration and detailing.
- On the interior, will the rehabilitation cause loss of significant historic fabric or seriously damage th historic character?
- Will there be a professional on site during construction to ensure that work is carried out according to established preservation principles.
- Have construction personnel received adequate training in undertaking historic preservation work?
Credits for Preservation
This information was originally prepared (as it appeared in Architectural Graphic Standards) by the following staff of the Preservation Assistance Division National Park Service: Lee H. Nelson, FAIA, H. Ward Jandl, Michael J. Auer, Charles E. Fisher, Anne Grimmer, Camille Martone, Sharon C. Park, AIA, and Kay D. Weeks.