As was the case Saturday, extreme cloud bursts now push our aging infrastructure to its limits and leave businesses and residences to deal with the aftermath.
We put together this quarter's Building Notes for anyone who owns, leases, or operates a property in New York City — seven straight answers on why this keeps happening and what you can actually do about it.
As a restaurant renovation contractor and storefront builder, we see the aftermath first-hand: flooded cellars, ruined walk-ins, swollen millwork and retail fit-outs that have to be torn out and rebuilt.
Building Notes · Vol. 02
Seven Flood Questions Answered
01
Why do NYC sewers back up during extreme rainfall?
When rainfall exceeds roughly 2 inches per hour, the sewer system can become overwhelmed. The DEP may also close tide gates to prevent river flooding, which further reduces drainage capacity and increases the risk of backups.
02
What risks do properties and businesses face during heavy rain?
Extreme rainfall can flood low-lying areas, overwhelm storefront entrances, fill basements and cellars, and force contaminated sewer water back into buildings through floor drains, sinks, and toilets. For restaurants, that means cellar prep areas, walk-ins and dry storage. For retail, it's stock rooms and the floor finishes right at the storefront threshold.
03
What's one of the smartest defenses against flood damage?
Install and maintain backflow prevention check valves. When the sewer system is overloaded, these valves help prevent wastewater from flowing back through your building's plumbing. They are the most effective low cost option but do come with maintenance cost so be prepared. If you're planning a restaurant renovation or a retail build-out, have your contractor price a backflow valve into the plumbing scope. It costs far less during construction than after a flood.
04
What can I do to help prevent flooding entering my business?
Keep an eye on clogged catch basins near your property and report issues to 311 with the exact location. The DEP takes these reports seriously. Be sure to also support regular street sweeping, keeping gutters clear helps keep water moving.
05
What's a hidden flood risk inside my property?
Floor drains are often the first entry points for sewer water. In restaurant kitchens and commercial buildings, many owners choose to block drains and raise floor sinks when the flood risk outweighs the convenience. Some residents and businesses have raised cellar toilets onto platforms. For what goes under the tile, see our notes on waterproofing.
06
How can my lease help protect me from flooding?
Do everything possible to have your lease clearly outline repair responsibilities, rent relief options, and flood prevention measures. Definitely demand the landlord disclose any past flood events and be cautious of any "As-Is" agreements that may shift existing problems onto you. Before you sign, have a tenant improvement contractor walk the space. Floor drains, cellar condition and the threshold height at the storefront door all show how a space has flooded before, and what the build-out will need to address.
07
How do you flood-proof a storefront renovation?
Raise the threshold where code and Landmarks allow. Use water-tolerant finishes below the flood line. Keep electrical panels, equipment and millwork off cellar floors. Install a backflow valve. Then put who maintains all of it in the lease.
"You can't out-build a flood. But you can be the property owner who saw it coming — a maintained valve, a clean catch basin, and a lease that says who's responsible go a long way."
— Ted Kilcommons, RAMP Contractors
Foot Notes
Still here?!? 😊 ...Resources for the Flood-Prepared
Support Black Spring Books
HereHelp this Williamsburg community bookstore rebuild its storefront after the most recent flood.
NYC DEP
nyc.gov/depA 6,000 person machine moving over a billion gallons of wastewater out every day.
NotifyNYC
notifynyc.cityofnewyork.usNotify NYC warns you before the city goes sideways.
FEMA Flood Map Service
msc.fema.govLook up your property's flood zone before you sign a lease or start a renovation.
Ready to build something?
Planning a restaurant renovation, retail build-out or storefront renovation in Manhattan or Brooklyn? RAMP is a commercial general contractor for design-driven restaurant, hospitality and retail projects. Let's talk.
Let's Build!