Basement & foundation waterproofing in NYC
Water finds the weakest point in a building. We track leaks back to where they start — a foundation crack, a failed joint, a parapet, a roof edge — and fix the cause, not just the stain.
Waterproofing services
Basement waterproofing
Interior and exterior approaches for damp or leaking basements, including crack injection and sealing of walls and floor joints.
Foundation waterproofing
Repair of foundation cracks and application of waterproofing to foundation walls where they can be accessed.
Below-grade waterproofing
Membranes and coatings for areas below ground level, such as areaways, vaults and below-grade walls.
Facade waterproofing
Sealing and coating of brick and masonry facades, caulking around windows and joints, and repairs that keep wind-driven rain out.
Roof & parapet waterproofing
Flashing, coping and membrane details at roof edges and parapets where many top-floor leaks begin.
Leak investigation
Walking the building inside and out to identify the likely source of water before recommending a fix.
When to call
- Water on the basement floor after rain
- Musty smell or mold in the basement
- Peeling paint, bubbling or efflorescence on walls
- Cracks in foundation walls
- Top-floor ceiling stains near exterior walls
- Leaks around windows during storms
Common questions
Interior or exterior basement waterproofing — which is better?
Each has its place. Exterior work addresses water before it reaches the wall but needs excavation; interior systems manage water that gets through. The right choice depends on the building, access and budget, and we’ll walk you through the options.
Can you find where a leak is coming from?
We inspect the areas around the leak, inside and out, to identify the most likely source and explain our reasoning before recommending repairs.
Is facade waterproofing the same as painting?
No. Waterproofing products and sealants are designed to shed water while letting masonry breathe. The right product depends on the wall material and its condition.
Waterproofing across NYC
- Waterproofing in Brooklyn
- Waterproofing in Queens
- Waterproofing in Manhattan
- Waterproofing in The Bronx
- Waterproofing in Staten Island
Other services: Masonry · Concrete · Roofing · Violation removal · Commercial
Waterproofing guides
Plain-English answers to the questions NYC owners ask us most, with links to the official City sources.
7 Signs Your Brick Needs Repointing (and What Proper Repointing Involves)
Eroded and cracked joints, spalling brick, efflorescence and interior damp — what they mean and how proper repointing is done.
Read the guide →GuideBasement Waterproofing Options for NYC Homes: What Actually Works
Figure out where the water comes from, then compare drainage fixes, crack injection, interior systems and exterior membranes.
Read the guide →GuideFlat Roof Leak Repair Checklist for NYC Homes and Buildings
Where flat roofs leak, what to check, when to repair vs. replace, and what NYC’s Local Laws 92/94 mean for a full replacement.
Read the guide →