Mills Building

Placed on the National Register of Historic Places in 1977, the Mills Building is one of San Francisco’s architectural gems. Located at 220 Montgomery Street in the financial district, the Mills Building sports a decorative façade of terra cotta, brick and marble with intricately carved designs. Built in 1890, it survived the 1906 earthquake, albeit with severe damage, and was soon after rebuilt and enlarged. The accompanying Mills Tower was added later in 1931. The Chicago style building had withstood nearly a century of wear before its renovation in 2002-2003. Since then, accumulation of impurities has obstructed both the Montgomery Street face and the Bush Street face of the building.

ARG Conservation Services was contracted to survey the building façade and to clean all terra cotta, brick, and marble masonry surfaces. After testing for a suitable material to clean the masonry, the entire facade was cleaned to remove soiling and foreign materials, revealing the architectural details of the building. The conservation approach helped to preserve the quality of the façade and protect the historic integrity of this important city icon.