Renovating an occupied, historic building in the heart of Midtown Manhattan is tough. And the project at 640 Fifth Avenue was no exception, requiring a unique combination of construction management and logistics to redevelop the 267,000sf, 18-story office building, as well as add three stories on top.
Built in 1949, the limestone-clad building was occupied through the first eight floors throughout the renovations and additions. The team’s biggest challenge, then, was to devise the best logistical and construction approach to successfully perform the work without disrupting the building’s tenants and retailers, as well as the steady stream of nearby pedestrians frequenting Rockefeller Center.
The potential for disruption included all phases of construction, from erecting the new steel structure and glass curtain wall to building a temporary roof and reinforcing the steel columns. One solution was to eliminate the use of a hoist to load materials to the upper floors of the building during the construction phase. Instead, the team used a tower crane that also served to erect the structural steel.
To shelter the occupied floors, our team stripped the limestone façade from the 18th floor to the 10th floor and constructed a temporary protective roof. Construction then involved selective terrace and structural demolition, new structural steel and reinforcement of existing support members from the 9th floor up. We then replaced and relocated the mechanical and electrical equipment in a phased sequence, all while keeping the systems operating for the occupied floors.
With a standardized floor plate and common leasable floors, the new and improved building totaled 302,000sf of gross office space in 21 stories.