SGH interviewed building staff to understand the location and frequency of water leakage, studied related documents, conducted a survey to identify leakage locations, and developed repair options ranging from noninvasive to wholesale repair of the original below-grade waterproofing.
Since the below-grade garage projected under a public sidewalk, repairing the structure was particularly challenging and the project team had to balance the technical solutions with access requirements.
During our field work, we identified ongoing water leakage at the grade-level slab under the 15th Street sidewalk, planter walls, and concrete beams. We also observed leakage-related deterioration of structural members.
SGH developed short-term and long-term repair approaches. In the short-term, we recommended implementing an iterative and thorough negative-side injection program until more comprehensive repairs could be implemented. Our long-term recommendations included excavating around the building and installing new waterproofing around the grade-level slab and planters combined with negative-side repairs to the below-grade structure and targeted repairs at foundation wall penetrations.