Water at a skylight
Skylight leaks are slow and the wood around the opening rots quietly. If it only appears in cold weather it may be condensation, not a leak at all.
What is probably happening
- Condensation. VELUX says condensation can drip between the frame and the rough opening, giving the appearance of a leak, and it happens more in cooler weather when the temperature difference is greatest.
- Failed flashing around the skylight curb, the most common true leak.
- A cracked or failed seal in the glazing itself. InterNACHI's chart puts a skylight's life at 10 to 20 years.
Do this in the next five minutes
- Note when it happens. Only in cold weather with no rain points to condensation. During or after rain points to a leak.
- Wipe the glass and the frame dry, then watch. Beads forming on the glass from the inside is condensation.
- Photograph the stain and the skylight from below.
- If it is condensation: run the bathroom and kitchen fans, use a dehumidifier, and open the skylight shade so warm air reaches the glass.
- If it is a leak: put a bucket down, photograph, and book a roofer to inspect the flashing and the skylight seal.
Do not
- Do not caulk around the skylight from the roof as a first move. Sealant over failed flashing traps water instead of shedding it.
- Do not go on the roof to look. Photograph from the ground and let the roofer do the climb.
- Do not replace the skylight because a salesperson says so before the flashing has been ruled out.
Who to call
A licensed roofing contractor
Flashing and curb work is roofing. If the unit itself has failed, the roofer replaces it or brings in the skylight manufacturer's installer.
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What it should cost
$454 to $1,515
Skylight repair, national range, average $961. Replacement $1,200 to $3,500.
Source: Angi, skylight repair cost, updated September 2026. View source
National published range, not a quote for your job. The full cost table for this trade is on the roofing page.
Ask this contractor, on the phone, before anyone comes out
Tap each one as you ask it.
- Is this condensation or a leak, and how did you tell the difference?
- Is the leak in the flashing, the curb or the glazing seal?
- If you recommend replacement, is a flashing kit for my roof type included?
- How old is this skylight, and does the manufacturer still warrant it?
End the call if
- A replacement quote for a skylight that has only ever dripped in cold, dry weather.
- A repair that is only 'seal around it' with no flashing inspection.