Presidio Chapel Historic Structure Report - Presidio Trust

PRESIDIO CHAPEL (BUILDING 130)SAN FRANCISCO, CALIFORNIADeteriorated condition of roof flashing in bell room at the top of the bell tower.ConditionThe two lowest finished spaces of the bell tower are in good/fair conditionwith minor wear and deterioration of features and finishes. Given the degreeof material failure and water infiltration of the two uppermost levels, they aredeemed to be in poor condition.Issues & Recommendations• Handrails on interior stairs should be replaced or altered to extend beyondthe top and bottom risers to meet access requirements. The height ofinterior stair handrails should be altered to comply with code.• The existing stair width is too narrow to meet code requirements, but mayremain as an original building element under the Historic Building Code.• For both aesthetic and safety reasons, it is recommended that the stairseither be resurfaced or upgraded.• The roofing, flashing, and/or sealant at the chimney cap has failed andsignificant amounts of water are pooling inside the chimney as well asalong the chimney walls, leaving water streaks in the upper bell towerroom and bell tower stairwell. Water infiltration, efflorescence, and plasterdelamination is concentrated at the bottom of the chimney surroundingthe ashpit door in the boiler room hall, but the source of the water clearlyoriginates at the top of the chimney.• The seals around both exterior windows have failed and water appears tobe pooling on the sills, causing efflorescence, plaster delamination, andorganic growth around and below both exterior windows. Efflorescence onthe interior plaster surface suggests that water is being transported throughthe material, causing delamination of the finish coat, and may be corrodingthe embedded steel. To alleviate delamination caused by efflorescence, thetransportation of water around the windows and through the concrete mustbe mitigated. A qualified structural engineer should assess the conditionof the concrete. Once the source of the water is identified and corrected(see water infiltration treatment below), then the crack and adhesion can berepaired using Big Wally’s Plaster Magic or similar product (see below forinterior plaster treatment recommendations).• Furthermore, the missing trap door has left the upper bell tower room opento the elements. So as not to exacerbate water infiltration problems further,the trap door should be replaced and properly sealed.Page & Turnbull61PART III: TREATMENTRECOMMENDATIONS