Transforming a Historic Upper West Side Co-op Roof Into a Deck: Challenges Ahead

The reality quickly set in for the Manhasset, a historic Upper West Side co-op, when it discovered that transforming their sprawling 17,000-square-foot roof overlooking the Hudson River into a fabulous roof deck would require far more than a carpenter, some green thumbs and $150,000. “The board thought they could just put a wooden deck up on the roof and be done,” says Kevin Bone, a principal at Bone Levine Architects. What the board didn’t know when they began their seven-year journey is that today’s roof deck requires overcoming significant regulatory hurdles that increase cost and time. 

Reality quickly set in when Bone recommended starting with a feasibility study — a suggestion that initially shocked board members. This crucial planning step, costing around $20,000, revealed the project's true complexity. The feasibility study uncovered more than just regulatory hurdles. It revealed that the building needed a complete roof replacement — something that had to be addressed before any amenity construction could begin. "The board wisely committed to not spending any money on this passive recreation area until the top floor shareholders were protected from ongoing leaks that had plagued the building for years," says Bone.

The feasibility study also revealed a maze of regulatory requirements that would shape every aspect of the project. First came structural considerations—could the existing building support additional weight?  "A roof terrace requires verification of structural capabilities; identification of exit and egress situations; and identification of occupant load, fire safety compliance and accessibility," Bone explains. At The Manhasset, this required invasive probing both from the roof and inside apartments "We had to get some sense of what the existing building skeleton was like to determine if the additional live loads of this new terrace structure could be carried safely according to DOB regulations,” he explains.

Fire safety compliance added another layer of complexity. "One of the glories of a big roof is that it's a big roof and you have a lot of space. One of the disadvantages is you have long travel distances to the stair bulkheads," notes Bone. This impacted the layout and positioning of recreational areas, which must not exceed maximum travel distances to stairways. Accessibility under the Americans with Disabilities Act presented further challenges. “Typically, the rules say you’re not allowed to use lifts to accommodate this access,” Bone notes. Many elevators stop below roof level, so providing accessible routes can require raising elevator cabs—a significant capital expense—or using adaptive lifts that allow wheelchair users to transition between levels via stairs. “That was in fact how we filed the Manhasset and how we got it approved."

The Manhasset faced a singular challenge - it functions as one co-op but exists as two separate buildings in DOB records.  “Everything had to be calculated based upon the fact that there were two buildings, two primary stairwells, and it was very important that all shareholders be treated more or less equally,” Bone says.

These regulatory hurdles are not merely bureaucratic obstacles but essential safeguards that protect shareholders and ensure equitable access. “The feasibility study helped put a number on this project because ultimately it’s about can you do it in compliance with regulation, and can you do it in a way that’s affordable to the co-op?”

For others dreaming of rooftop amenities, Bone recommends starting with a dose of reality: these projects demand early and thorough investigation of code compliance, structural capacity, fire safety, and accessibility. “If you jump into it without a feasibility study, you risk surprises, delays, and escalating costs,” he warns. The Manhasset's modest $150,000 vision grew into a million dollar investment in both building infrastructure and quality of life—a testament to what Bone identifies as the three essential ingredients for successful long-term projects: "vision, planning, and perseverance."