Presidio Chapel Historic Structure Report - Presidio Trust

HISTORIC STRUCTURE REPORTFINALTREATMENT OF STAINED CONCRETE FLOORSProtection, Maintenance, and InvestigationClean concrete floors regularly and re-seal on a periodic basis to protect againstthe high wear to which these floors are subject. Provide regular maintenance ofpainted concrete floor surfaces, including removal of cracked and peeling paint,reapplication of new compatible paint, and regular cleaning.TREATMENT OF INTERIOR ORNAMENTAL METALSProtection, Maintenance and InvestigationThe majority of the ornamental metals used in the Presidio Chapel are found inthe door and window hardware. Before undertaking any repair or replacementefforts, the type of metal, its finish, and assembly methods should be examinedand documented.RepairWhere stained concrete floor colors have faded, the existing floor surfacefinishes should be stripped, and the floor should be carefully ground to removeprevious stains. Apply new penetrating concrete stains to match the original,unfaded colors. New stains and colors should be tested on a relatively hiddenarea of concrete prior to general use. Stain materials should be applied byqualified personnel who have experience in concrete treatments of this type.After staining treatment, floors should be sealed and protected from traffic untilnew colors and finishes have cured completely.In cases of minor cracks, they may be filled and repaired using epoxy, which shouldmatch the characteristics of the existing concrete, including color and texture.Cleaning/RefinishingTo remove unwanted paint from ornamental metals and historic door/windowhardware, first brush all peeling and loose paint from the surface using a stillnatural bristle brush; do not use wire brushes. Then, apply a thixotropic/alkalineformulation paint stripper approved for removing paint coatings from ornamentalmetal work, such as “Sure Klean 509 Paint Stripper.” Allow stripper to remain onthe surface as recommended and then brush or rinse with water and blot dry.To clean and polish unpainted ornamental metal surfaces and apply a new clear finish,first apply a chemical cleaner such as “SureKlean 887 Stainless Steel Cleaner. Spongeor rinse with clean water to remove chemical and loosened dirt. Polish in accordancewith industry standards, and then apply protective lacquer finish, as needed.ReplacementNo replacement work is recommended for historic tinted concrete floor slabs. Ifthe condition of the concrete floor warrants replacement, and it is not feasible tocover or resurface the historic concrete floor, then the entire concrete slab maybe removed and replaced in-kind using modern construction methods.ReplacementOrnamental metal replacement materials must match existing metal to be replacedin shape, thickness, type of metal and finish. Many of the manufactured hardwareitems may be available from the original supplier or as a quality reproduction.ReferencesSee the U.S. General Services Administration’s Historic Preservation TechnicalProcedures for Ornamental Metalwork.92MARCH 2012