Carolands Mansion
500 3rd Street
1 Hacker
300 Hamilton
60 Spear Street
60 Spear Street photo

60 Spear Street
San Francisco, CA

Concrete Spalling Services

CAWC was called to inspect concrete spalling on this building's exterior surfaces. The building has pre-cast concrete panels from the first floor to the twelfth, with punched windows on every floor. We performed a Rilem tube test to determine the absorption rate of the concrete surface. Water absorption into concrete is a common problem, but the rate and volume of absorption is key; it determines the appropriate remedy. The objective is to prevent moisture from reaching the structural reinforcing steel. Water corrosion of structural steel will cause spalling of the concrete. On a building like this, spalling can create both a hazard for pedestrians and an associated personal injury liability for the building owner. If left untreated, the structural integrity of the entire building can be degraded.

Upon completion of the Rilem tests, we concluded that the concrete on this building had a high absorption rate and showed evidence of spalling. Our recommendation was to apply complete a waterproof coating system to stop water absorption. The owner requested a smooth surface finish to resemble the original panels. We accomplished this by hand troweling a concrete repair mortar over the entire surface. Then, a high-build coating system was applied to seal the existing cracks and provide protection from future cracks and spalling. We also applied new silicone sealant to the expansion joints around the window frames and panel-to-panel joints for a comprehensive protective shield.