How do you maintain a skylight?
Updated August 2026
Most skylight leaks are flashing leaks, not glass leaks, so the yearly job is inspecting the flashing and seal once a year and after storms and keeping the curb and weep channels clear of debris. The perimeter seal and gaskets last 10 to 20 years before they dry out, and leaves piling against the upper edge are what dam water into the flashing. Stay ahead of it and you avoid the classic outcome: a slow flashing leak that soaks the drywall below and costs $500 to $2,000 to put right once the ceiling is stained.
| Task | Interval | Effort |
|---|---|---|
| Inspect flashing and the perimeter seal for cracks and gaps | Yearly, after storms | 15 min · DIY |
| Check the interior ceiling and drywall for fresh stains | Yearly, after storms | 10 min · DIY |
| Look over the glass or dome for cracks and fogging | Yearly | 10 min · DIY |
| Task | Interval | Effort |
|---|---|---|
| Clear leaves and debris from the curb and above the skylight | Each season | 15 min · DIY |
| Wipe condensation and check for mold at the frame edges | Each season | 10 min · DIY |
| Task | Interval | Effort |
|---|---|---|
| Clear the weep channels that drain the frame | Every 2–3 years | 15 min · DIY |
| Service gaskets on an operable, venting unit | Every 2–3 years | $20–50 DIY |
| Task | Interval | Effort |
|---|---|---|
| Reseal the flashing or replace an aged unit | 10–20 years | $500–1,500 pro |
What neglect costs
A skylight leak is sneaky because the water enters at the flashing high on the roof and travels before it drips, so the stain shows up feet away and the source hides for months. In that time it wets the drywall, the insulation in the light shaft, and the framing, growing mold and softening the ceiling. What starts as a $30 tube of flashing sealant becomes a leaking-skylight repair of $500 to $2,000 once you are replacing drywall and repainting, and a rotted shaft or a unit swap pushes it higher. The yearly flashing check is the cheap side of that.
Leave these to a pro
Reflashing a skylight properly means working shingles and step-flashing back into the roof, which is a roofer's job, not a bead of caulk over the top; caulk-only "repairs" are why so many skylights leak again. Budget $500 to $1,500 to reseal or reflash, and roughly $1,000 to $3,000 to replace an aged unit with drywall repair. A yearly professional look makes sense once the skylight passes 15 years or if you have a stain you cannot trace. Clearing debris, checking for stains, and wiping condensation are all safe DIY from inside or a stable ladder.
This whole checklist ships as reminders in OnOtto: every task above, on the right schedule for your home, snooze-proof.
Load this checklist as remindersFrequently asked questions
Is it condensation or a leak?
Condensation collects as fine, even droplets or fog on the inside glass and frame, is worst on cold mornings and in humid rooms like baths and kitchens, and wipes away without returning until conditions repeat. A leak is different: it shows as a running drip, a spreading brown stain on the ceiling or shaft, or water that appears specifically during and after rain. If wiping the glass dry solves it and it only returns with weather changes, it is condensation. If a stain grows and tracks with rain, treat it as a flashing leak.
Can I reseal a skylight myself?
You can handle the easy, safe parts: clearing debris from the curb, wiping the weep channels, and running fresh sealant on an operable unit's gaskets. The flashing itself is another matter. A real reseal often means lifting shingles and redoing step-flashing, high on a roof, and a caulk-only patch usually fails within a season and hides the leak while damage continues underneath. If the leak is at the flashing rather than a gasket, that is a roofer's job. Track the reseal interval on the reseal schedule.
How long do skylights last?
The unit itself commonly lasts 20 to 30 years, but the seals and gaskets are the shorter-lived part, drying and failing at 10 to 20 years, which is when leaks and fogged glass tend to start. A fogged, hazy pane means the insulated glass seal has failed and the unit is near the end of its service life. Flashing done right can outlast the glass. Plan on resealing at least once during a skylight's life and replacing the whole unit as it approaches 25 to 30 years.
Why does my skylight only leak in winter?
A skylight that drips in winter but stays dry in summer rain is usually not leaking at all, it is condensation or an ice dam. Warm indoor air meets the cold glass, condenses, and runs down like a leak. Or snow melts on the warm roof, refreezes at the cold eave into an ice dam, and backs water up under the shingles and past the skylight flashing. The fixes are different from a plain leak: reduce indoor humidity, improve attic insulation and ventilation, and keep the roof edge clear.