After Hurricane Ida, a Brooklyn Co-op Vows: Never Again

When Hurricane Ida blasted New York City in 2021, she dumped a record three inches of rain in an hour, causing major flooding that left 16 New Yorkers dead. A month earlier, Hurricane Henri had doused the city with a then-record two inches of rain in an hour. While the Sterling Atrium co-op in Brooklyn’s Park Slope was spared any loss of life, the city’s overtaxed storm sewer system sent water pouring into the basements of the co-op’s two century-old buildings during both storms. The repeat flooding was a last straw for the co-op board.

“With global warming, this is only going to get worse,” says Michael Gordon, 69, an original shareholder in the co-op and now the president of its board. “We started to look into what we could do.”

The board was in luck. It had already engaged RAND Engineering & Architecture to address leaks on the roofs, which feature two large skylights and several smaller ones — the sources of the natural light that gives Sterling Atrium its name. The board asked the engineers what could be done to prevent future flooding.

“They told us a system of valves and ejector pumps would stop the sewer backups and put an end to the flooding,” Gordon says. “These pumps would force water back into the city’s sewer system.”

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Andrew Briguet, a mechanical engineer at RAND who’s serving as project manager on the flood-control phase of the project, explains that it will consist of two components. First, a backwater valve will be installed in each basement, which will prevent water from the overtaxed storm sewer system from backing up into the basements. Then each building will be equipped with duplex Sulzer ejector pumps, which will bypass the backwater valves and use high pressure to expel any water that enters the basements from sources other than the storm sewer. The cost of this phase of the project is expected to be about $250,000. 

Much more costly is the roof replacement. After years of patching, Gordon and the board decided to strip the roof down to the wooden deck and rebuild it from scratch, adding insulation for the first time.

“The skylights are big, and they leak,” says Grace Gallagher, the RAND engineer who’s overseeing the roof replacement. “I’m going to propose probes to confirm the existing assembly. Then we’ll write a budget letter and prepare requests for proposals to send to contractors.”

Gordon estimates the total cost of both projects will be about $2 million, which the board will cover with money from the recent refinancing of the underlying mortgage. No assessment or maintenance increase will be required.

“Over the years, we’ve had roofers come and go,” he says. “They would put another layer on the membrane and then leave. This time we’re going to install state-of-the-art roofing material which the manufacturer guarantees.”

The planning of the roof and drainage projects has gotten a boost from the cooperation of shareholders. “When you tap into people who live in the building, you get additional skill sets,” Gordon says, noting that several shareholders work as property managers and understand the intricacies of a job like this. “The tricky thing we’re up against now is hiring the right contractor,” he adds. “Some contractors may not have the skills to take on a project of this size. Very few people want to work with these skylights because they’re so big.”

Work will begin soon and take about a year. Gordon is hoping it gets finished before the next hurricane hits. “We don’t want to have to sweat any more big storms,” he says. “They’re very unpleasant.”

PRINCIPAL PLAYERS — ENGINEER: RAND Engineering & Architecture. PUMP MANUFACTURER: Sulzer.