Inside 25 Water Street:
The Nation’s Largest Office-to-Residential Conversion At 1.1Msf, the transformation of 25 Water Street into SoMA is the largest office-to-residential conversion in US history. Turning a 1960s-era office tower into more than 1,300 apartments—with a 10-story overbuild and 100,000sf of luxury amenities—was a design and construction feat. For Pavarini McGovern, the job meant solving complex challenges on a tight timeframe.
“
We don’t do 1,300 apartments too often,” SAYS JOSEPH
structural changes with long-term performance pushed the design and construction teams to think outside of the box.
STROSS, PROJECT MANAGER AT
“Just the sheer volume of turnover in such a short period of time—it was history-making.” PAVARINI MCGOVERN.
SHEDDING LIGHT According to Brooks McDaniel, SVP of building repositioning at STOBG, windows are one of the most common challenges of office to residential conversions—and 25 Water Street was no exception. “The back of the building needs light and air in New York, which requires a certain amount of depth between the window and the rear lot line,” McDaniels explains. “Windows also need to open in residential buildings, but many office buildings have fixed curtain wall façades that weren’t designed to open.” To meet light and air requirements, the team cut thousands of new openings into the concrete façade—a daunting process that also required an entirely new waterproofing strategy. Balancing these 12 | Issue 3 2025 STOBG Insights
The conversion included adding 10 stories above the office tower
“There just wasn’t enough window space,” recalls Joseph Lacertosa, project executive at Pavarini McGovern. “It was mock-up after mock-up with our engineering team on-site every day, figuring out how to build the waterproofing system backwards. We spent hours refining those details.”
PLUMBING PREP The conversion also meant rethinking MEP systems from the ground up, and restrooms were one of the team’s top concerns. “An office building is designed for multi-stall bathrooms, not hundreds of individual ones,” explains Stross. “We had to use back outlet toilets instead of floor outlets, shift bathrooms left and right around the steel structure, and make sure everything fit.” Justyna Drozdz, MEPS coordinator at Pavarini McGovern, remembers the intensity of that coordination. “I joined the construction team on-site during demolition and stayed through nearly a year of clash detection meetings. Every day we were solving puzzles—where to run pipes, where to put penetrations. I literally had dreams about the model. I could walk through it in my sleep.”