How Many People Can Go Up on a Co-op or Condo Roof?

Q: We have two rooftop lounges on top of our Hell’s Kitchen condominium building, where I serve on the board. There are maximum capacities for the lounges listed in the building’s offering plans, but they seem too low — the spaces have double doors and double exits for easy evacuation in case of emergency. How do we find out how many people can legally be in these lounges at the same time?

A: For a rooftop lounge or patio to be legal, it must be listed on the building’s certificate of occupancy, along with the purpose of the space, the maximum number of people allowed and load limits, replies the Ask Real Estate column in The New York Times. You can find your building’s certificate of occupancy on the Department of Buildings’ (DOB) website under Building Information System, or on DOB NOW for certificates issued as of February 2021.

(If your building was built before 1938, the year New York City began requiring the certificates, you could check with the DOB to see if it is legal through a Letter of No Objection.)

The city determines maximum occupancy using a number of factors. These include dividing the square footage by the occupant load factor listed in chapter 10 of the city’s building code. The formula typically yields a smaller capacity for a rooftop space compared to a similar indoor space, for safety reasons. Another factor is the width of the stairs, for speedier exits during emergencies.

Having a rooftop capacity that exceeds 74 people most likely triggers a requirement for a place of assembly certificate, which involves additional fire safety requirements and potentially greater insurance costs, says David Maggiotto, deputy press secretary for the DOB.

It’s possible that the listed limits in your offering plans are indeed lower than what city code allows. Perhaps the board, years ago, wanted to keep activity and noise on the roof to a minimum, or avoid the costs associated with the city’s place of assembly requirements. “The board has a right to be restrictive,” says Bruce Cholst, a partner at the law firm Herrick Feinstein.

If your rooftop lounge is not permitted, you can hire an architect or engineer to draw plans for the space, then have those approved by the city. After construction, your building can be issued a new certificate of occupancy that includes the rooftop lounge. Then you'll know exactly how many people can go up on the roof.