Most skylight leaks come from the flashing around the skylight, not the glass. Old or tarred flashing, missing step flashing or a curb set too low lets water in during heavy rain. Other causes are a failed seal between the glass and frame, a cracked plastic dome, debris piled on the uphill side and condensation on the glass that runs down and looks like a leak.
The common causes
| Cause | Clue |
|---|---|
| Flashing | Water at the corners or down the shaft walls, often in heavy or windy rain |
| Glass or frame seal | Water or fog between panes, drips from the frame |
| Cracked dome | Visible crack, often after hail or a falling limb |
| Debris on the uphill side | Leaves and needles piled against the skylight |
| Condensation | Drips on cool mornings, no rain, over bathrooms or kitchens |
Why flashing is the usual culprit
Many skylights around Pine Bluff were added in remodels in the 1980s and 1990s, and some were flashed with tar or caulk instead of a proper flashing kit. That holds for a few years, then cracks in the sun. Skylights also sit in the path of water running down the roof, so any gap on the uphill side takes a lot of water in a hard rain. See why a roof leaks only in heavy rain.
How to tell a leak from condensation
Condensation forms on the inside of the glass when warm, moist air from the house meets the cooler glass. It shows up on cool mornings without rain and drips down the frame, most often over bathrooms and kitchens. A leak shows up with rain. Running a bathroom fan and keeping humidity down reduces condensation. See roof leak or condensation.
The fixes
- Reflash: Remove shingles around the skylight, install new step flashing and a proper flashing kit, and reshingle. This fixes most leaks.
- Clear debris: Keep the uphill side clear, especially under pines.
- Replace the unit: If the glass seal has failed, the dome is cracked or the frame is rotted, a new skylight is often the better fix. It should be reflashed at the same time.
- Remove it: Some owners choose to remove a problem skylight and roof over the hole.
See skylight leak repair.
How long do skylights last?
Many skylights last about 15 to 20 years before seals or domes start to fail, though that varies by brand and exposure. If the roof is being replaced and the skylight is past that age, replacing the skylight at the same time avoids tearing into the new roof later.
Hail and skylights
Plastic domes crack in hail, and glass skylights can too. After a hailstorm, look at skylights from inside for cracks or new water spots. Damage from a storm may be part of an insurance claim. See signs of hail damage on a roof.
Can I seal a skylight myself?
Caulk around the edge can slow a leak for a while, but it does not fix flashing. And sealing over weep holes on some skylights traps water inside the frame. See is caulk a permanent roof fix.
Do all skylights eventually leak?
Not if they are flashed well and kept clear of debris. Seals and domes do age, though.
Is it the skylight or the flashing?
Water at the corners or down the shaft in heavy rain usually means flashing. Fog between panes means the seal.
Should I replace my skylight when I replace my roof?
If it is 15 to 20 years old or more, it is often worth doing at the same time.
Can a leaking skylight be removed?
Yes. The opening is framed, decked and roofed over to match.