Why Your Skylight Is Leaking (and the Real Fix)
Skylights leak more than almost any other roof feature — but here's the surprise: the skylight itself is rarely the problem. In our experience across Bothell, the culprit is the flashing around the skylight curb about 80% of the time. Here's how to tell what's actually wrong and what the lasting fix looks like.
The usual suspects, in order
Failed curb flashing is number one: step flashing that's corroded, lifted, or was never installed correctly lets water in around the unit. Number two is underlayment failure around the curb — the waterproof layer beneath the shingles deteriorates faster at penetrations. Number three is the skylight-to-curb seal drying out. Actual skylight unit failure — cracked frames, failed glass seals — comes in a distant fourth.
Then there's the impostor: condensation. On cold mornings, warm moist indoor air condenses on cold skylight glass and drips — looking exactly like a leak, but it's a humidity and ventilation issue, not a roofing failure. Rule of thumb: drips during rain = leak; drips on cold dry mornings = condensation.
What a proper skylight repair involves
We lift the surrounding roofing, remove the failed flashing, renew the underlayment around the curb (integrated correctly with the field underlayment), install new step and head flashing, and reseal the unit to the curb. If the skylight itself is fogged between panes or the frame is compromised, we'll recommend replacing the unit — with all-new flashing, which is half the value of the job anyway.
When replacement beats repair
Consider a new skylight when the glass is permanently fogged, the frame is cracked or warped, the unit is 20+ years old with obsolete seals, or you're already paying for a full flashing rebuild and the incremental cost of a new unit is small. Modern skylights also offer much better energy performance — a nice bonus.
Leaking skylight? Roof Leak Repair Services diagnoses leak vs. condensation honestly and rebuilds the flashing right. Call (888) 974-0663 for a free estimate in Bothell.
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Dealing with an active leak? Roof Leak Repair Services is your local licensed expert — call (888) 974-0663 for a free estimate. Our call representatives are available 24/7 for emergencies.