Leaking or fogged skylight? Repair and replacement in Vancouver, WA

Not every wet skylight is leaking. Condensation builds up on cold glass and runs down the shaft, especially in a steamy bathroom or on a cold winter morning. A real leak usually shows up during or right after rain, often worst at the upper corners, where water and debris back up against the curb. Our first job is telling the two apart, because the fix is completely different.

When it is a true leak, the cause is usually the flashing, not the glass. Many older skylights were set with sealant and a bit of metal instead of a full step-flashing kit, and that sealant gives out after a few winters. Other times the unit itself is done: cracked acrylic domes, failed glass seals that fog between panes, or rotted wood curbs. Then replacement is the better answer.

Leak or condensation

Condensation is common on older skylights with single-pane glass or acrylic domes. Warm, moist indoor air hits the cold glass, beads up and drips. It happens most in bathrooms and kitchens and on cold, dry mornings, not during rain. If the drips show up when it has not rained for days, it is almost always condensation, and the fix is better venting in the room, a newer insulated unit or both.

A true leak follows the weather. Stains that grow after a storm, drips that start an hour into a heavy rain or wet drywall at the top of the shaft point to water coming in from outside. We confirm by checking the shaft and attic during or right after rain, and by water testing the roof around the skylight one side at a time, starting low and working up. That tells us which side is letting water in.

Common causes of skylight leaks

Most leaks come down to a few failures we see again and again. Fixing the wrong one wastes money, so we trace the water before anything gets torn off. If the unit is sound, a reflash may be all it needs. If it is not, we price replacement alongside so you can choose with the full picture in front of you. Photos from the roof make the choice easy to follow.

• Sealant-only flashing that has cracked
• Missing or rusted step flashing on the sides
• Debris dammed against the upper curb
• Rotted wood curb under the flashing
• Cracked or crazed acrylic dome
• Failed glass seal letting water into the frame

Repair or replace the skylight

Repair makes sense when the glass is clear, the frame is solid and the problem is the flashing or a section of sealant. We remove the shingles around the skylight, install a proper step-flashing kit or new pieces, add an underlayment collar and relay the shingles. That gives an older unit a second life. It is also the right fix when the skylight is fairly new but was installed poorly to begin with.

Replacement makes sense when the unit itself is failing. Fogged glass means the insulating seal is gone, and the unit will not get better. Cracked domes, warped frames and soft curbs also call for a new skylight. Replacing it with a modern laminated, low-E unit and its own flashing kit fixes the leak and usually cuts condensation and heat loss as well. Many new units also come in the same rough opening sizes as older ones, which keeps the inside work small.

Swapping during a reroof

If your roof is near the end of its life, plan the skylight work with the reroof. Flashing a new skylight into new shingles and underlayment is cleaner and cheaper than reflashing it now and disturbing it again in two years. Older skylights rarely outlast a new roof, so most homeowners replace them at the same time. If the reroof is still a few years out, a careful reflash now can carry the skylight until then, and we will tell you which route makes more sense for your roof's age.