Why skylight leaks come back after they're sealed
Most skylight leak repair in NYC is a bead of sealant around the glass. The water is usually not coming through the glass. It comes in at the skylight curb, where the roof membrane meets the frame, or through corroded flashing, cracked gaskets and weep holes that were painted shut. A leaking skylight that was resealed last year and is leaking again this year is telling you exactly that.
A skylight curb is a roof penetration like any other. The membrane has to turn up the curb and be terminated under a counterflashing, the counterflashing has to lap over the membrane, and the frame has to drain to the outside. When any one of those fails, resealing the glass buys a season at most — the water simply enters below the sealant line.
We treat a leaking skylight as a roofing detail. We strip the curb back to sound material, rebuild the flashing in the same system as the roof, reset or replace the frame, and only then address the glazing. That order is why our skylight leak repair holds and the sealant job did not.
Where skylights leak, and what we rebuild
Curb & Membrane Tie-In
The membrane turn-up at the skylight curb is the most common failure. Short turn-ups, unbonded laps and old mastic over granules let water in below the frame. We strip and re-flash the curb in modified bitumen or liquid PMMA so the tie-in is part of the roof again.
Counterflashing & Metal
Corroded or lifted counterflashing exposes the top edge of the membrane. We replace it with new metal set into a reglet or under the frame, lapped correctly so water runs over the joint rather than into it.
Gaskets, Glazing & Frames
Dried gaskets, cracked acrylic domes and racked frames do leak, but only after the curb has been ruled out. We reset or replace the unit once the flashing is right, so the new skylight is not blamed for an old curb.
Condensation vs Leak
Winter dripping on a cold morning is frequently condensation, not a roof leak. We test for both before anyone pays for skylight leak repair they do not need. If it is condensation, the fix is insulation and ventilation at the shaft, and we say so.
Free Skylight Leak Inspection
Every call starts with a roof-side and interior inspection at no charge. We water-test the curb, the flashing and the glazing separately so the repair is aimed at the detail that is actually letting water in.
Stop Skylight Leaks at Source
The source is almost always the curb. Rebuilding it in the roof's own system is the only repair that survives freeze-thaw. That is how we approach every leaking skylight in Manhattan, Brooklyn, Queens and the Bronx.
Permanent Fixes, Not Patches
A tube of sealant is a patch; a rebuilt curb is a repair. We do not sell the first one as the second. If a skylight has been resealed more than once and still leaks, the curb and flashing are the job, and that is what the estimate will say.
Commercial Skylight Repair
Warehouse ridge units, retail light wells, stairwell and shaft skylights on pre-war co-ops: the curb detail is the same discipline on all of them, but access, fire rating and tenant protection differ. We plan each one as a roofing job, with the shaft protected and the roof around the curb inspected while we are up there.
Recent NYC projects
Skylight leak repair, step by step
Inspect from the roof and from inside. We look at the curb, flashing, frame and glazing on the roof, then at the shaft and the ceiling below, because the two views together usually identify the entry point.
Water-test the curb, flashing and glazing separately. Flooding the whole skylight proves there is a leak; isolating each component proves where. Fifteen minutes of methodical testing saves a repeat visit.
Written scope. The estimate names the component, the repair method and whether the unit stays or goes. If the roof around the curb is also failing, we tell you, because a new skylight on a wet roof is wasted money.
Rebuild the curb flashing in the roof's system; reset or replace the unit. Our in-house roofers do the flashing, our crews set the frame, and the glazing is addressed last. All DOB-compliant.
Photo close-out. Before-and-after photos of the curb and flashing, a note on the condition of the surrounding roof, and a direct line if anything changes after the next storm. The repair is documented so the board or managing agent has a record for Local Law 11 files and for the next roofing decision.
What NYC building owners say
Leaking skylight?
Free skylight leak inspection, Manhattan to the Bronx.
Frequently Asked Questions
Stop skylight leaks at the source.
Curb and flashing rebuilt right, so the next storm stays outside.
Related: Roof Leak Repair NYC