Anne Grimmer is a senior Architectural Historian with the Preservation Assistance Division of the National Park Service; Paul K. Williams is a Cultural Resource Manager with the Air Force. Both authors wish to thank the following individuals for the technical assistance they provided in the preparation of this publication: Edna Kimbro, Architectural Conservator, Watsonville, CA; Edwin S. Krebs, AIA, K. Norman Berry Associates, Louisville, KY; Melvin Mann, TileSearch, Roanoke, TX; Walter S. Marder, AIA, Division of Historical Resources, Tallahassee, FL; Gil Sánchez, FAIA, Gilbert Arnold Sánchez, Incorporated, Santa Cruz, CA; Terry Palmiter and Sandra Scofield, Alfred, NY; and National Park Service professional staff members. In addition, the authors wish to thank Karin Murr Link, who produced the drawings which illustrate this Brief.

Washington, D.C. September, 1992

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.