Is it a skylight leak or condensation?
A skylight leak shows up with the rain, and condensation shows up with the cold. If the glass is wet on the inside but the roof was dry all night, the culprit is humidity. If the light well is stained, the drywall is soft or water drips during a storm, the roof is letting water in.
Check two things before you call. Note whether the stain is still damp after several dry days, and look at the pattern. A ring around the whole frame points to the sealant or the curb. A line on one side points to the flashing on that side. A drip from the glass seam points to failed glazing. That diagnosis steers the repair.
What causes a leaking skylight in Alameda?
A leaking skylight in Alameda comes from four things, and age sits behind all of them.
- Dried sealant around the frame, cracked by decades of sun.
- Step flashing that has lifted at the sides or corroded.
- Head flashing that does not carry water over the top.
- A rotted curb or deck below the unit.
The rain makes it show. About 22 inches fall each year, almost all of it October through April (BestPlaces), so a unit that held through a dry summer can leak with the first storm. Alameda's housing is old too, with 31.9% of homes built in 1939 or earlier (Point2Homes), so skylights added decades ago have been through many cycles of sealant.
How we inspect a leaking skylight
We inspect from both sides. Inside, we look at the light well for stains, softness and mold. On the roof, we check the sealant, the flashing on all four sides, the curb, the glazing and the shingles around the unit. Wayne or Pedro often does the visit.
A moisture reading on the curb and well tells us how far the water has traveled. If the wood is dry and sound, a reseal and reflash is realistic. If it is soft, the job grows to include framing. You get photos of what we found and a written estimate that separates the options.
Repair methods: reseal, reflash or replace
Three repairs cover most calls, and each has a place.
- Reseal: new sealant around the frame and the counterflashing, for a unit that is sound and a leak that is minor.
- Reflash: pulling back the shingles, rebuilding step and head flashing with new metal and membrane, then reinstalling the courses. It fixes most real leaks.
- Replace: a new unit when glazing is cracked, fogged or crazed, or when the curb is rotted. See skylight replacement.
Caulk alone is the repair we avoid. A bead of sealant over failed flashing buys a few weeks, then peels. Sealant is part of a good repair, but flashing is the repair.
What a skylight repair includes
- Inspection inside the light well and on the roof, with photos
- Moisture reading on the curb and well
- Reseal, or reflash with new step and head flashing
- Replacement of damaged shingles around the unit
- A water test of the finished joint, then cleanup
A unit that is being added, not repaired, gets its flashing built from scratch, and the skylight installation page describes how.
What a skylight repair visit looks like
- You call and describe the stain and its timing. Past customers report a visit within a day.
- We inspect the unit, the light well and the roof around it.
- If rain is coming, we put temporary protection over the leak first.
- You get a written estimate with photos and repair and replacement priced separately.
- We repair the flashing and sealant, replacing damaged shingles around the unit.
- We test the joint, wipe down the glass and light well, and clear the site.
- Photos of the finished work reach you the same day.
We fix the roof and document interior damage for your insurance or records.
Fix skylight leak cost: what moves it
A skylight repair cost depends on how deep the problem goes. Resealing a frame is small, reflashing is larger, and a repair that reaches a rotted curb and deck adds carpentry. Roof covering matters too, since tile and metal take more care than shingle, and access, pitch and the number of units set labor.
We publish no per-unit price because we have no verified local number. Our estimates are free, and a second opinion helped one customer see that a much higher patch quote elsewhere was too high. A written estimate is the only price you can hold anyone to, so ask for reseal, reflash and replace as separate lines.
Keeping a repaired skylight dry
Inspect the sealant each fall, before the first rain. Keep leaves and debris off the upslope side, where water dams. Clean glass with mild soap, not solvents, which attack sealant and acrylic. A condensation problem can be eased with a bathroom fan, a cracked-open window or a dehumidifier, none of which touch the roof.
Permits and licensing for skylight repairs
A reseal or reflash is the lightest case, but check with the City of Alameda Permit Center, which says most construction work needs a permit. For an emergency repair, the City's permit page says the application is due the next working business day. If the unit itself is swapped, the energy-code limits on the NFRC label apply (BayREN). The minor-work exemption covers only jobs under $1,000 that need no permit and involve no employees (Business and Professions Code §7048), and roofing work needs a C-39 classification. Look up any roofer at cslb.ca.gov.
Where we repair skylights
Skylight leaks are a call we take across the East Bay from Webster St. Oakland is about 12 minutes away, Berkeley roughly 18 and San Leandro about 24, with freeway traffic and the tubes as the unknowns.