San Francisco, CA

100 Montgomery (Formerly 120 Montgomery)

Scope/Solutions
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Project Summary

Scope/Solutions

100 Montgomery (formerly 120 Montgomery) was originally designed by Wilbur D. Peugh to serve as the headquarters for Equitable Life Insurance. Constructed in 1955, the twenty-five story office building is considered a historically-significant structure in downtown San Francisco and is distinguished by its white marble facade and Art Deco window framing. SGH was retained to perform a condition assessment of the exterior enclosure as part of a pre-purchase survey. It was during this survey that we noted distress to the marble panels. The owner retained the property and hired SGH to determine the cause of the panel cracks and develop repair options.

We determined that panel cracks were due to corrosion of embedded aluminum support angles and expansion of the marble cladding. SGH developed repair options that ranged from pinning the marble in-place to overcladding. When Hines and Sterling American Property acquired the building in 2006, they elected to undertake a three-year, $30 million redevelopment plan and retained Robert A.M. Stern Architects. SGH worked as the building enclosure consultant to the contractor for the rehabilitation and highlights of our work include the following:

Oversight of trial installations for the owner’s consideration
Worked with owner to obtain City of San Francisco approval for the crystallized glass panels
Development of overcladding details for the contractor
Design of new supports for the crystallized glass panels that are drilled through the existing marble panels
Coordination with the construction manager and facade contractor to develop cost estimates and provide value-engineering alternatives
Oversight of proof testing for panel anchors and crystallized glass
Quality-control inspections of panel installation and associated anchors