Roof Repair
Skylight leak repair in San Jose
A wet skylight shaft does not always mean the skylight is leaking. Sometimes it is the flashing around it, sometimes a failed seal in the glass, sometimes condensation. The fix depends on which, so we find out first.
What we treat
- Concrete and clay tile
- Composition shingle
- Flat, torch-down and TPO
- Spray foam
- Standing seam metal
Quick answer. Skylight leak repair in San Jose starts by separating flashing leaks, which show during rain, from glass seal failures and condensation, which do not. Flashing and curb leaks are fixed by rebuilding the step flashing or curb cap; cracked domes and failed glass units are replaced; condensation is solved with ventilation, not roofing.
Updated September 2026
The job
Four causes, four different fixes
Timing is the first clue. Water that appears only during rain is almost always flashing or the curb. Water that appears on cold mornings with no rain is condensation. Fogging between the panes is a failed seal in the glass unit.
Caulking the outside of a skylight is the most common wrong fix. It seals the path water was supposed to drain out of and moves the leak somewhere else.
What happens after you call
How a skylight leak visit runs
- 1
Ask about timing
Rain only, cold mornings, or always.
- 2
Inspect inside
Shaft, frame and glass for the source.
- 3
Inspect outside
Flashing, curb and covering around it.
- 4
Water test
Hose test on the flashing if the cause is unclear.
- 5
Repair the cause
Flashing, curb, dome or unit.
- 6
Confirm
Tested again before we leave.
Warning signs
Signs a skylight needs attention
- Stains on the shaft walls
Water is running down from the frame.
- Drips during rain only
Flashing or curb is the likely cause.
- Fog between the panes
The glass seal has failed.
- Yellowed or crazed dome
The acrylic is near the end of its life.
- Caulk piled on the frame
Earlier quick fixes that often trap water.
- Water on cold, dry mornings
Condensation, not a leak.
Jobs this page covers
Curb and flashing leaks
Most skylight leaks come from the flashing around the curb, not the unit. Step flashing that was face-nailed, a headwall flashing too short to lap under the course above, or a curb too low for the roof pitch all let water in during wind-driven rain. We remove the shingles or tile around the curb, rebuild the flashing in the right sequence, raise the curb where it sits too low, and relay the covering. Rotted curb framing is replaced while it is open.
Cracked acrylic domes
Acrylic domes turn yellow and brittle in the sun and crack at their fastening points. A cracked dome can sometimes be replaced alone if the curb and frame are sound, which is quicker and cheaper than a full unit. When the frame is corroded or the dome size is no longer made, we replace the whole skylight with a current unit that fits the existing opening, or reframe the opening to a standard size so the next replacement is simple.
Failed seals on glass units
Moisture or haze between the panes of a glass skylight means the seal has failed and the insulating gas is gone. It is not a roof leak, but it can drip at the frame when condensation builds inside. The glass unit, or the whole skylight on older models, is replaced. If the skylight is more than about fifteen years old and a re-roof is coming, it is usually better to replace it then, flashed into the new roof. Some manufacturers still warrant the glass, so we check the label first.
Condensation versus a real leak
Warm, moist indoor air meeting cold glass leaves water that runs down the shaft and looks exactly like a leak. It shows on cold mornings, in bathrooms and kitchens, and after showers, with no rain involved. The fix is ventilation: an exhaust fan that vents outside, a venting skylight that can open, or insulating the shaft walls. We tell you when that is the answer rather than tearing into a roof that is not leaking. A humidity reading in the room often settles it in minutes.
What we see on San Jose roofs
A lot of the skylights we repair sit on low-slope roofs, especially in San Jose's early Eichler tracts, like Rose Glen near San Jose City College and Fairhaven out toward Campbell, where the roofs are mostly foam or built-up systems. On those roofs a skylight curb that is too short sits in water every storm, and foam or built-up flashing around it has to be renewed each time the roof is recoated, which is why curb height is the first thing we check.
Do it yourself or call us
What to try yourself and what to leave to us
Some skylight water is solved from inside the house.
| Task | Doing it yourself | Having us do it |
|---|---|---|
| Run the bath fan longer | Often cures condensation | We check the fan vents outside |
| Wipe and watch on a dry day | Tells you if it is condensation | We confirm with a hose test |
| Caulk around the outside | Traps water and moves the leak | Flashing rebuilt in sequence |
| Climb up to look | Risky, especially on tile | Roped and booted |
Cost
What a skylight leak repair costs depends on
Repairs are priced once we know which of the four causes it is.
- The cause Flashing rebuilds, dome swaps and full units differ widely.
- Roof covering Tile and flat roofs need different flashing work.
- Curb condition Rotted or low curbs are rebuilt or raised.
- Unit availability Odd sizes may need the opening reframed.
- Interior damage Drywall in the shaft is repaired by another trade.
- Access Steep or two-story roofs add setup.
FAQ
Questions we get asked
Many flashing and curb leaks are repaired without replacing the unit. Cracked domes and failed glass are replaced.
Wind-driven rain reaches flashing that normal rain does not. The flashing sequence is usually wrong.
No. It is a ventilation problem, and we tell you when that is the case.
If they are older plastic domes, yes; it is far cheaper than later.
Yes, often by raising the curb.
Same category
Related roofing work
Shingle Roof Repair
Torn, missing and curling shingles, nail pops and ridge caps on composition roofs.
Learn moreTile Roof Repair
Cracked and slipped tiles, failed underlayment and valley repairs on concrete and clay.
Learn moreFlat Roof Repair
Ponding, blisters, split seams and foam cracks on low-slope roofs.
Learn moreRoof Flashing Repair
Chimney, wall, skylight and vent flashing rebuilt so the joint stops leaking.
Learn moreFind out what is really causing the drip
Tell us when the water shows up. We find the cause first, then fix that and nothing more.