General GSA Maintenance Guidelines

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.


Park, S. C. "Preservation Brief 47:Maintaining the Exterior of Small and Medium Size Historic Buildings". Washington, D.C.: U.S. Department of the Interior, National Park Service, Heritage Preservation Services, June 2007.


Proper custodial care counters the forces that cause deterioration of the building fabric, such as:

  1. Erosion and abrasion

  2. Chemical deterioration

  3. Corrosion

  4. Mold

  5. Birds, insects, and plant materials

  6. Human behavior

Buildings require cleaning because weathering and human activity deposit potentially harmful particles on surfaces. Dirt particles abet abrasion and are often a factor in chemical deterioration processes. Occasionally, special techniques are required to counteract the electrostatic attraction between dirt and certain surfaces, or to arrest or reverse various ongoing chemical changes caused by dirt on sensitive materials.

In historic buildings, where the materials are older, less resistant to abrasive and chemical action than their contemporary counterparts, and frequently irreplaceable, special consideration of the following custodial guidelines is warranted:

  1. Understand the nature of both the dirt and the surface to be cleaned before proceeding. Dry cleaning processes (e.g., dusting, polishing, vacuuming, etc.) will remove over half of the dirt, usually at little risk to the structure; wet cleaning (e.g., mopping, washing, etc.) including the use of soaps, detergents, polishes and other compounds to suspend and emulsify dirt particles, are necessary to clean the other half.

  2. Use the mildest workable method and cleaning solution in each instance; this may require more time or effort.

  3. Refer to historical precedents regarding how the materials have been cared for before choosing a new custodial process.

  4. Research and test the suitability of new products before permitting their widespread use on an historic building. Seek the experiences of others before proceeding. Begin work in the less sensitive, less valuable areas of the structure.

  5. Remember that decisions involving the care of historic buildings frequently involve the lesser of two evils; in some instances, historic materials that might be damaged by repeated cleaning may be better preserved if they remain dirtier than custodial standards would otherwise permit.

  6. Clean ONLY when a useful purpose is served; do not clean historic materials simply because they are old.

In general, the standard custodial practices of the General Services Administration (refer to GSA Custodial Management Handbook, PBS P 5810.2 A) are well-suited to the normal demands of interior cleaning in historic buildings, and most external cleaning problems (e.g., cleaning of glass, architectural metals, etc.; consult Part 3 of the Handbook for the special case of masonry cleaning).

The procedures and policies of the GSA regarding the maintenance and repair of conventional buildings (refer to HB, Building Maintenance Management, PBS P 5850.1A) are also applicable to GSA's historic buildings, although changes in emphasis are frequently necessary.

Because a range of alternatives must be considered when confronting any maintenance or repair problem, the following questions are useful:

  1. Has the problem and its remedy been identified, or have only the symptom?

  2. Are the resources available to solve the problem on a long-term basis?

  3. If not, are visually and technically acceptable interim alternatives available?

  4. What are the implications of taking no action or delaying action until a better solution or additional resources are at hand?

  5. Does the contemplated maintenance or repair action involve the irreversible alteration or destruction of significant fabric? Is the projected benefit worth the risk?

  6. Can the situation which caused the problem be remedied by changing the cause rather than treating its result (e.g., reducing the load to eliminate the overstress; changing the use pattern to diminish wear and tear, etc.)?

  7. What can be learned from maintenance or repair records about previous attempts to solve the problem?

  8. Have other GSA personnel confronted comparable problems in similar buildings?