Foundation Waterproofing NYC
Foundation waterproofing in NYC for new construction and existing buildings, done from the outside where water first meets the wall. We install exterior membranes and drainage that stop water before it ever reaches the foundation, including on tight lots where the wall sits right against the neighbor.
- Exterior Membranes & Drainage
- New Construction & Repairs
- Licensed & Insured
What Is Foundation Waterproofing?
Foundation waterproofing is a waterproof barrier applied to the outside of a building’s below-grade walls, the side that faces the soil. It stops groundwater and rainwater at the surface of the wall, before they can soak into the concrete or masonry. A complete system usually pairs a waterproof membrane with a drainage layer and a drain at the footing, so water that reaches the wall is carried away instead of building up against it.
It’s the most complete way to keep a foundation dry, and it’s standard for new buildings with basements, cellars, or below-grade spaces. On existing buildings, it means excavating along the foundation to expose the wall, which makes sense when leaks are severe, when the old exterior coating has failed, or when a basement is being renovated and needs lasting protection.
Foundation Waterproofing in NYC From the Outside
Whether the wall is going up for the first time or has been leaking for decades, the goal is the same, a continuous barrier on the side where the water is.
New Construction Foundations
Membranes, drainage, and footing drains installed as below-grade walls are built.
Existing Foundation Repairs
Walls excavated, cleaned, repaired, and rewaterproofed where old coatings have failed.
Walls Against Neighbors
Blindside systems for foundations built right at the property line.
Signs Your Foundation Needs Exterior Waterproofing
Leaks That Interior Fixes Can't Stop
Water still getting in after sealing and drainage inside.
Seepage Across Whole Walls
Dampness spread across large areas, not one crack.
Crumbling Old Tar Coating
Original exterior coatings flaking off where the wall is exposed.
Water Pooling Outside the Wall
Wet soil or standing water along the foundation after rain.
A Basement Renovation Ahead
A finished space planned that needs dry walls for good.
A New Building With Below-Grade Space
Cellars, basements, or parking levels in new construction.
Why NYC Foundations Let Water In
Foundation leaks usually trace back to what’s happening, or missing, on the outside of the wall.
Failed Exterior Protection
Many older foundations only had a thin tar coating, which cracks and breaks down over the decades.
High Groundwater
Low-lying areas and sites near the water can keep foundations sitting in wet soil for much of the year.
Missing or Clogged Footing Drains
Without a working drain at the base, water collects around the foundation instead of flowing away.
Foundation Waterproofing Systems We Install
The system depends on the site, the depth, and whether we can reach the outside of the wall.
Sheet & Fluid-Applied Membranes
Continuous waterproof membranes bonded to the exterior face of the foundation.
Drainage Board & Footing Drains
A drainage layer and perimeter drain that carry water away from the wall.
Blindside Waterproofing
Membranes installed before the concrete is poured, for walls built against a neighbor.
Our Foundation Waterproofing Process in NYC
Exterior waterproofing is only as good as the preparation behind it.
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Excavate & Expose
The soil is dug out along the foundation to expose the wall down to the footing.
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Clean, Repair & Waterproof
The wall is cleaned, cracks and voids are repaired, and the membrane is applied.
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Drain, Protect & Backfill
Drainage and protection board go on, footing drains are set, and the soil is backfilled.
Zero Lot Line Buildings
When a new foundation sits right against a neighbor’s wall, waterproofing has to go in before the concrete, using a blindside system.
Excavation Near Neighbors
Digging along a foundation next to other buildings can require permits and protection for adjoining properties, which is planned before work starts.
NYC Considerations for Foundation Waterproofing
Building close together below grade is one of the things that makes NYC foundation work different.
What Affects Foundation Waterproofing Cost in NYC
Foundation waterproofing is priced by the site as much as by the wall, since access shapes the whole job.
Wall Depth & Length
How much foundation wall needs waterproofing.
Excavation & Access
Machine digging versus hand digging on tight lots.
Membrane System
The type of membrane suited to the site.
Drainage Work
New footing drains or connecting to existing ones.
Site Restoration
Walkways, driveways, and landscaping put back.
Neighboring Structures
Protection and permits for work near adjoining buildings.
Foundation Waterproofing Projects in NYC
Why Builders and Owners Choose Us for Foundation Waterproofing
A foundation is waterproofed once and then buried. There’s no second chance to get it right, so we treat every detail as if it has to last the life of the building.
Waterproofing at the Source
Water stopped on the outside, before it reaches the wall.
Drainage Built In
Membranes paired with drainage, never on their own.
New Construction Ready
Work sequenced with your excavation and concrete schedule.
Engineer & GC Coordination
Systems installed to the project's drawings and details.
Clients on Our Foundation Waterproofing
Foundation Waterproofing Across NYC & Westchester
We waterproof foundations for new buildings and existing homes throughout four NYC boroughs and Westchester County.
Brooklyn
New construction and row house foundations.
Queens
Houses with yards and new multi-family buildings.
Bronx
Foundations for new and existing residential buildings.
Manhattan
Below-grade walls on tight urban sites.
Westchester
Home foundations and new construction across the county.
Foundation Waterproofing FAQs
Exterior waterproofing makes the most sense for new buildings with below-grade space, for foundations where the original coating has failed, and when leaks are too widespread for interior fixes. It's also worth considering before finishing a basement, since it protects the wall itself. For the inside approach, see basement waterproofing.
Dampproofing is a thin coating that slows moisture moving through the wall, but it can't hold back water under pressure. Waterproofing is a continuous membrane designed to stop water even when groundwater presses against the foundation. Building codes call for waterproofing where groundwater conditions require it.
It's waterproofing installed before the foundation wall is poured, applied to the shoring or the neighboring wall. It's used in NYC when a new building goes right up to the property line and there's no room to reach the outside of the foundation later.
Footing drains run along the base of the foundation and carry away water that collects there. Without them, water builds up around the wall and pushes harder against the waterproofing. A membrane and a drain work best together.
For new construction, yes, using a blindside system before the concrete goes in. For existing buildings where the outside can't be reached, the wall is usually protected from the inside with drainage and crack injection.
Some disturbance is unavoidable, since the soil along the foundation has to come out. We plan the dig to limit the area affected, and walkways, driveways, and landscaping are put back once the backfill is in.
Yes. We install foundation waterproofing as part of new construction projects, following the project drawings and fitting into the excavation and concrete schedule.