Basement Waterproofing in Union Square, Manhattan

Why Does Water Get Into Union Square Cellars?

Union Square has no particular flood exposure beyond heavy rain, so cellar water here usually comes from ordinary sources: runoff pooling at the foundation, porous old masonry, leaking pipes and failed sidewalk drainage. Finding the right source decides what repair will actually work.

Many buildings around the park are commercial, and their cellars hold storage, mechanical equipment and shop inventory. A damp cellar costs money quickly, ruining cartons and corroding equipment. Retail owners notice it first at the stockroom door.

Sidewalk vaults add a wrinkle. A vault under the public walk can leak when rain finds the cover seams or the slab above. The water then runs along the wall into the building cellar.

What Does Waterproofing Involve in a Building With No Yard?

Most Union Square buildings sit on the lot line, so there is no yard to dig. We work from inside: seal wall surfaces, install a drainage channel along the base and send collected water to a sump pump. Where an area or vault gives outside access, we can treat the exterior too.

The interior system does not stop water from reaching the wall. It controls where that water goes. Sealing cracks and failing joints reduces how much arrives, and the channel and pump handle the rest.

We plan the work around commercial operations. Stockrooms need to be cleared, so we agree on what moves and when. Dust and noise are scheduled for quiet periods.

What if the leak comes from a vault under the sidewalk?

Vault leaks involve the sidewalk structure. We inspect covers, seams and the slab above. If the slab or ceiling is failing, an engineer should review before repair, and sidewalk work will need a DOT permit that we file.