Skylight Leak Prevention: Keep the Sun In and Water Out

Skylights have a leaky reputation, but most water problems come down to a failed seal, trapped debris, or simple condensation — all preventable. Four checks keep yours dry: inspect the seal, clear the debris, diagnose condensation vs. leak, and reseal properly.

How do I inspect a skylight for leaks?

Inspect the exterior seal and flashing around the frame (from the roof, safely, or with binoculars). Skylight leaks usually start at the flashing and sealant where the unit meets the roof, not the glass. Look for cracked or peeling sealant, lifted flashing, and gaps. This perimeter is where the vast majority of real skylight leaks originate.

Why clear debris around a skylight?

Clear leaves and debris from around the skylight. Debris dams up against the upper edge, holding water that eventually finds its way under the flashing — the same way clogged gutters cause leaks. Keep the area, and any cricket/diverter behind it, clear so water flows around and past the unit.

Is it a leak or just condensation?

Crucial to distinguish condensation from an actual leak. On cold days, warm indoor humidity condenses on the cool glass and drips — that's a humidity issue (run exhaust fans, lower indoor humidity), not a roof leak. A true leak shows up during or after rain and stains the surrounding ceiling. Diagnosing correctly saves a needless roof repair.

How do I reseal a skylight?

If the seal has failed, reseal the frame with a skylight-rated (or roofing) sealant — clean out the old, failed sealant first so the new bead bonds, then apply it where the frame meets the flashing. For lifted flashing or recurring leaks, the flashing itself needs attention, which is roofer territory on a steep roof.

Track the checks

Logging skylight inspections and reseals helps you watch a known trouble spot. Okoniq Property Hub keeps it with your home maintenance records in one private place.

Frequently asked questions

Why does my skylight only "leak" in winter?

That's almost always condensation, not a leak — warm, humid indoor air hitting cold glass. Improve ventilation and lower indoor humidity; a true leak tracks with rain, not temperature.

How long do skylights last?

Quality skylights last 15–30 years; the seals and flashing typically fail before the unit. Inspect the perimeter yearly and reseal as needed to get the full lifespan.

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