A delicate renovation and expansion of a 1949 structure, work on 640 Fifth Avenue progressed while tenants remained in the first eight floors, requiring innovative solutions to construct the project’s 30,000-square-foot addition.
To avoid disturbing the tenants, new framing above the 10th floor transferred loads to exterior columns. An existing truss for the previous ground floor banking hall was reinforced, taking the interior columns and new transfer columns to where the new roof setbacks were created. The existing exterior limestone façade was stripped from the 18th floor down to the 10th and was replaced with a glass curtain wall with floor-to-ceiling windows. This provided unobstructed views over St. Patrick’s Cathedral and rooftop gardens in Rockefeller Center. The limestone at the base of the building was cleaned and re-pointed, with new windows installed.
In order to bring outdated mechanical and electrical equipment up to code, the team replaced and relocated these systems in a phased sequence, while keeping systems for the occupied floors operating. New cooling towers and a water tank were installed above the existing ones, with the three-story addition built around them before removing the old systems.