Leader House Retail Expansion

A multi-level mixed-use retail plaza and glass structure were added to the fully-occupied 30-story, 280-unit "Leader House" residential property on Manhattan's Upper West Side.

The striking glass multi-level addition provides new retail on the first floor as well as 17,000 square feet of commercial space in the building’s cellar and sub-cellar and a 9,500 square foot rooftop terrace / garden area above the new structure. The new commercial and retail spaces offer ceiling heights ranging from 15 to 18 feet. 

The project’s significant structural modifications included extensive demolition of the original building lobby and retail space as well as the removal of the existing structural slabs and steel between the first floor, cellar and sub-cellar levels.  Additionally, Mc Gowan excavated thirty-feet deep into rock to expand the basement footprint. The project required installing twenty-five tons of new steel for temporary shoring to support the building, including the installation of 30 steel whalers and wood lagging for the new excavation, waterproofing at the structural connections to the old foundations and reinvigorating the subsurface drainage with additional ejector pumps.

The project scope entailed installation of all new MEP systems as well as the installation of new meter rooms for electric and gas service, including altering the building’s oil burner equipment to accept gas. To serve the new commercial and retail spaces a new redundant boiler system, cooling tower and fire alarm system as well as four new hydraulic elevators and two escalators were installed. The building’s underground parking garage accommodates 127 vehicles.

One of the more demanding project concerns was in avoiding disruption of the fully occupied high-rise Leader House residential building with daily construction activities, which Mc Gowan handled by organizing and implementing protocols to address daily site safety and logistics.