Award of Excellence: High-Rise Category
Restoration of 945 Green Street
San Francisco, California
Submitted by Sika Corporation
Neumann Sloat Blanco Architects, LLP
San Anselmo, CA
Concrete Science, Inc.
Alpha Restoration & Waterproofing
South San Francisco, CA
Vector Corrosion Technologies
Winnipeg, MB, Canada
Located on Russian Hill, 945 Green Street is one of the most iconic residential buildings in San Francisco, CA. Offering breathtaking city and bay views, this exclusive cooperative is located near famous landmarks such as Lombard Street and across from Alcatraz Island. After almost 100 years in service, the 14-story building was beginning to show major signs of deterioration, including spalling, cracking, and exterior delamination.
This building, built in 1920, was steel frame construction with reinforced concrete slabs and exterior. As with many buildings in the area, it has been subjected to the marine environment, which led to corrosion of the reinforcement and steel frame over time. Small repairs were conducted periodically, but due to restrictive access to the exterior of the building, large-scale restoration had been avoided. In 2012, the observable repairs were significant enough to warrant a full-scale investigation. Although it was apparent the tower was in need of repair, the full extent of these repairs was still unknown.
The weeklong corrosion inspection revealed many areas of severe carbonation and chlorides leading to the need for extensive concrete and reinforcement repairs. Not only did corrosion play a large part in the repairs but throughout the years, many of the finer architectural details had also been lost. So while repairs were being made, the owner used this time to recreate and replace many of these details, including columns, arches, and a fountain. With many obstacles throughout the process, work has remained constant and on schedule. Work has been ongoing since 2012 and Phase 2 was completed in early 2014.