Today: keep the units dry
We seal the leak area with patching compound or a weighted cover. With water coming in right now, after hours or in a storm, we start here.
Flat Roofers NY · Queens
Concrete Flat Roof Leak Repair in Queens
Concrete flat roof leak repair from Flat Roofers NY stops the water coming through your slab the same day. Then we trace the leak source and make the repair permanent.
Leak sources
Six places water gets into a slab roof
Each one shows up differently inside.
| Leak source | What you see inside | Our repair |
|---|---|---|
| Parapet wall and coping | Damp top-floor walls | Reset coping, repoint joints |
| Flashing at walls and bulkheads | Stain where wall meets ceiling | New flashing and counterflashing |
| Expansion joint | Straight-line leak across rooms | New joint cover, resealed |
| Roof drain and scupper | Wet ring near a riser | Reseal drain flange, clear scupper |
| Cracks in the slab | Drips, rust stains | Seal or inject the crack |
| Ponding water spots | Stain under low spots after rain | Patch, plus a drainage fix when water keeps sitting |
Leak tracing
Why the stain isn't over the leak
Water runs along a concrete roof deck before it drips. So the ceiling stain can sit well away from the leak.
-
Roof inspection
Seams, flashing and drains, piece by piece.
-
Water test, section by section
We wet one area at a time while someone watches below.
-
Mark and photograph
You see the source before any repair starts.
Stop it today, fix it for good
Next visit: the permanent repair
Once the water test confirms the source, we repair the slab, flashing or drain properly. Then we test it again.
Repair methods
Four ways a slab roof leak gets fixed
The method depends on where the water gets in.
Crack injection
Fills cracks that run all the way through the slab, from the inside.
Crack sealing and patching
For surface cracks and spalled spots, with repair mortar.
Flashing, coping and drain repair
Handles leaks at the edges and outlets.
Liquid-applied membrane
Worn surface all over? We recoat it after the leaks are fixed.
Why fix it now
What fixing it now saves your building
Water left in a slab reaches the rebar. The steel rusts and swells, cracking concrete loose. That's the spalling, rust stains and white efflorescence you see below.
Concrete flat roof leak repair done early keeps ceilings dry and the slab sound, and heads off structural work or replacement later. We explain how a slab roof is built and waterproofed on its own page.
Yes, all of them. Terraces and garage decks mean working around pavers or traffic coating. For leaks reaching top-floor apartments, we coordinate access with the board or super.
The source comes first. Coating over an open crack or failed flashing only hides it for a season.
Yes. The temporary stop goes in during bad weather. The permanent repair waits for dry, warm enough conditions.
Free estimate
Get your slab roof leak found and fixed
Tell us the building type and where the water shows inside. We'll check the roof and price it free.
Rather talk it through?
Call Flat Roofers NY(917) 473-9811