Why Skylights Leak — and When It's Not the Skylight's Fault
Most skylight leaks trace back to flashing, not the glass itself — here's how to tell the difference before paying for the wrong repair.
The flashing versus unit distinction
When a skylight leaks, the instinct is to blame the skylight itself, but in our experience the flashing around the curb — not the glass, seal, or dome — is the more common culprit. Distinguishing between the two determines whether the fix is a reflash or a full unit replacement, which are very different costs.
Signs it's a flashing issue
Water staining that traces to the edges or corners of the skylight opening, rather than the center, typically points to flashing failure. This is especially common on older installations where step flashing was integrated poorly with the surrounding shingles, or where sealant was used as the primary barrier instead of proper metal flashing.
Signs it's the unit itself
Fogging between glass panes, visible cracking in the dome or glazing, or a degraded gasket seal around the frame point toward the unit itself needing attention rather than the surrounding flashing. This is more common on skylights installed 15 to 20-plus years ago, as seals naturally degrade with age and UV exposure.
Why condensation gets mistaken for a leak
Not every drip near a skylight is a roof leak — condensation from temperature and humidity differences between the room and the glass can mimic a leak, especially in bathrooms or kitchens with higher humidity. We check for this specifically before assuming a structural leak is the cause.