NBC Studios – At 30 Rockefeller Center, in the heart of Midtown Manhattan, we installed a new 6000sf - 6” thick reinforced concrete Spring Lift Slab/Floating Floor System for the new home of the Tonight Show hosted by Jimmy Fallon. This type of floor system is used to minimize the transmission of noise and vibration directly thru the floor to spaces below. Lift slab floating floor systems incorporate spring isolator assemblies to decouple concrete slabs from non-isolated structural floors.
To install this system, first, perimeter isolation board is adhered to the perimeter of the floating floor area. Then, one (1) layer of poly sheeting is rolled-out across the structural slab and up the PIB, serving as a bond breaker between the non-isolated concrete structure and the concrete floor being floated. Next, isolator mounts are located and placed on top of the poly sheeting. Once the isolator housings are in place, steel concrete reinforcement bars are used to interconnect the mounts. Concrete is then poured to form a new slab. Once the concrete has cured properly, spring assemblies are inserted into the housings and the slab is carefully lifted using pneumatic tools to the specified height.
When the slab is lifted to specified height, the composite construction typically includes a 1" or 2" air cavity. However, on this project, the air cavity was 4”, twice as high as what is typically specified for this type of construction. Even more challenging was the fact that all work had to be performed off- hours and without the use of a concrete pump to transport the concrete from the street level up the 6th floor. In all, we poured 110 cubic yards of concrete utilizing 1 elevator and concrete buggies in one continuous 12 hour pour beating the owner’s schedule by 2 weeks.