Brick Waterproofing in NYC — Sealing, Repointing & Leak Repair

Free brick waterproofing assessment: (718) 772-8498 — or send photos of the staining, the crack or the damp interior wall on WhatsApp and we'll tell you where the water is getting in and what it takes to stop it. Every inquiry gets a response within 24 hours.

Why NYC brick buildings leak

Brick itself is rarely the culprit. On most of the leaking facades we inspect, the water is entering through everything around the brick:

• Failed pointing — mortar joints that have eroded, cracked or debonded after decades of weather. A wall can look solid from the sidewalk while every joint above the third floor is drinking at each rain.
• Hairline cracks — openings too fine to see from the street, yet wide enough for capillary action to pull water deep into the wall — where it travels and surfaces indoors somewhere entirely different.
• Parapets and copings — soaked from both faces and the top, the most weather-beaten masonry on the building. Open coping joints feed water straight into the wall below — many "roof leaks" are really parapet leaks.
• Wind-driven rain — New York storms don't fall politely downward. Rain driven horizontally against a tall, exposed facade forces water into openings ordinary rainfall never touches — it's why upper floors and corner exposures leak first.

We've written a full breakdown of the mechanics in our guide to why NYC brick buildings leak — but the short version: once joints and cracks are open, no surface coating will save the wall. The masonry must be made sound first.

The symptoms: efflorescence and ruined plaster

A wet brick wall announces itself in two places. On the outside, you see efflorescence — the white, powdery staining on brick that so many owners try to scrub off. Efflorescence is dissolved salts carried out of the wall by water as it evaporates from the surface. Cleaning it removes the stain; it does nothing about the moisture that delivered it. Recurring efflorescence on brick is a report card on moving water — every fresh bloom means the wall is still wet inside.

On the inside, the same water destroys finishes: plaster that bubbles and crumbles back to brown coat, paint that peels in sheets, staining that returns after every repaint, and the musty smell of a wall that never dries. Repainting is a losing game — interior plaster damage on an exterior wall is an exterior waterproofing problem, and it returns until the facade stops taking on water.

The right sequence: repoint first, then seal

This is where brick waterproofing goes wrong more often than anywhere else. A sealer — any sealer — is the last step, never the first. Our sequence:

1. Make the wall sound. Failed joints are ground out and repointed with properly matched mortar, hairline cracks are routed and repaired, spalled brick is replaced, and open parapet and coping joints are rebuilt or resealed. This is masonry and brickwork discipline, and it's where the actual leak gets fixed.
2. Let the wall dry. Sealing a saturated wall locks the moisture in. The masonry gets time to release the water it's holding before anything is applied.
3. Apply a breathable water repellent. We use penetrating, vapor-permeable repellents — the siloxane/silane family — that soak into brick and mortar and make them shed rain while still letting vapor escape from inside the wall.

What we won't do is coat a leaking wall with film-forming sealers, glossy "waterproof" paints or heavy elastomeric coatings as a shortcut. A film that blocks vapor traps moisture inside the masonry — and in a Northeast winter, that trapped water freezes, expands and pops the faces off the brick. We've stripped more failed coatings than we can count — on brick, breathability isn't a preference, it's what separates a protected wall from one being destroyed under its own coating.

Where the damage goes beyond joints — deteriorated lintels, failing sills, eroded brownstone detail — the work ties naturally into our exterior restoration scope, so one contractor carries the facade from repair through sealing.

What we inspect at the free on-site visit

Exterior waterproofing in NYC starts with finding the actual entry point, not the spot where the water shows up. At the free assessment we go over:

• Mortar joints — sounded and probed for erosion and debonding, floor by floor — not just at eye level
• Cracks — mapped and traced to their cause, because sealing over a moving crack just relocates it
• Parapets and copings — joints, caps and the roof-side face — the most common hidden source we find
• Window perimeters and sills — failed caulk joints and back-pitched sills that funnel water into the wall
• Previous coatings — anything already on the wall that's trapping moisture or will reject a new repellent
• The interior evidence — where the plaster damage and staining sit, matched against the moisture path outside

You get the findings straight, a scope that fixes the cause, and a fixed written quote — not an estimate that grows once the scaffold is up.

Freeze-thaw: the New York multiplier

A wet brick wall in a warm climate is a nuisance. A wet brick wall in New York is a demolition project on a timer. Every winter brings dozens of freeze-thaw cycles, and each one turns the water inside saturated brick and mortar into expanding ice. That's what spalls brick faces, bursts mortar joints and crumbles parapets — and it's why brick sealing in NYC pays for itself in the masonry repairs it prevents. A dry wall simply doesn't freeze apart.

How pricing works

No two facades take on water the same way, so we don't guess over the phone and we never publish flat rates. We visit your building free of charge, inspect the wall up close, and hand you a fixed written quote — no obligation, and no revisions after the work starts.

Your price is determined by:

• Repointing scope — how much of the wall needs joints ground out and repointed before any sealing happens
• Repair items — crack repairs, brick replacement, parapet and coping work, caulking at windows and sills
• Wall area and exposure — the square footage being treated and how the facade takes weather
• Access — ladder work vs. scaffolding vs. rigging changes the setup significantly
• Permits and filings — where the access or repair scope requires them, we handle the DOB and city paperwork as part of the job

We respond within 24 hours and can usually schedule the visit the same week. Start with the quote form or message us on WhatsApp.

Where we work

From our Yonkers headquarters we run waterproofing and masonry crews across Yonkers, the Bronx, Manhattan, Brooklyn, Queens, Staten Island and Westchester County. The pre-war walk-ups and rowhouses that dominate this housing stock are exactly where pointing, parapets and sealing give out together — the walls we work on every week.

Frequently asked questions

Stop the wall from drinking — starting this week

Whether it's one stained bedroom wall or a whole facade blooming with efflorescence, the first step is the same: we find where the water gets in, tell you honestly what the wall needs, and put a fixed price on it in writing.

Get a free quote

Prefer to talk? Call (718) 772-8498, message us on WhatsApp, email info@teknoconstruction.com, or contact us here. You'll hear back within 24 hours.