Definition
What is skylight leak repair?
Skylight leak repair finds and fixes water getting in around or through a skylight, whether from the flashing around its curb, the seals in the unit itself, or condensation forming on the glass.
A skylight is a big hole in the roof with a window in it. It depends on three things to stay dry: flashing that ties the curb into the surrounding shingles, seals between the glass or dome and its frame, and a surface warm enough that indoor humidity doesn't condense on it. When any of these fails, water shows up around the skylight well.
The tricky part is that all three look similar from inside: drips, streaks and stains around the opening. Guessing wrong means paying for new flashing when the problem is condensation, or resealing the glass when the flashing is at fault. Getting the diagnosis right first is a core part of leaking roof repair in Cibolo for homes with skylights.
Methods
How are skylight leaks diagnosed and fixed?
A roofer sorts the three causes by timing, location and what they see on the roof.
- Timing check. Leaks that appear only during rain point to flashing or seals. Moisture on cold mornings or humid days with no rain points to condensation.
- Where the water appears. Water at the top of the well or running down the drywall suggests flashing. Water between panes or at the frame suggests a seal failure. Beads across the whole glass surface suggest condensation.
- Roof-side inspection. The curb flashing, step flashing, head flashing and shingles around the skylight are checked for gaps, rust, lifted edges and debris buildup on the uphill side.
- Water test. The roof below the skylight is wetted first, then each side, then the glass, to isolate the leak.
Fixes follow the cause. Flashing problems are solved by resealing or, more often, installing a new flashing kit and resetting the surrounding shingles. Failed unit seals may be repaired on some models, but an older unit with failed seals is often replaced, ideally with new flashing at the same time. Condensation is addressed by reducing indoor humidity, improving airflow in the skylight well or upgrading to a better-insulated unit.
Debris on the uphill side deserves its own mention. Leaves and granules collect against the top of the curb, holding water there after every rain. Over time that water works past the head flashing. Keeping that spot clear, and making sure the flashing there is tall and well lapped, prevents a common repeat leak.
Warning signs
8 signs your skylight is leaking
Look at the skylight during and after rain, and again on a cool, humid morning, to see which of these apply.
- Drips from the skylight frame during rainSeals or flashing are letting water through.
- Water stains on the drywall around the wellWater is getting in around the curb.
- Fog or moisture between the panesThe insulated glass seal has failed.
- Beads of water on the glass on cool morningsIndoor humidity is condensing on cold glass.
- Peeling paint or bubbling in the wellRepeated wetting is damaging the finish.
- Rust or gaps in flashing around the skylightVisible from the roof or with binoculars.
- A cracked or crazed domePlastic domes can crack from hail and sun.
- Mold or mildew in the skylight wellMoisture has been present for a while.
Causes
What causes skylights to leak?
Skylights in the Cibolo area face intense sun, heavy downpours and occasional hail, which all speed up wear.
- Failed flashing. Improper step flashing, aged sealant or missing head flashing lets water in around the curb.
- Debris dams. Leaves and granules pile up at the uphill side and push water under the flashing.
- Failed glazing seals. Seals between glass and frame shrink and crack with heat and age.
- Hail damage. Plastic domes and older glass can crack from impacts.
- Condensation. Cold glass in a humid home, especially near kitchens and bathrooms.
- Old installation methods. Some older skylights were installed with sealant-only flashing that wears out quickly.
Skylights share the same weakness as any roof penetration: they depend on good flashing. See flashing repair for how the roof side of that system works.
Sun exposure matters more than people expect. A skylight on a south- or west-facing slope takes the full afternoon heat, which dries out gaskets and sealants faster than one on the shaded side. When a home has several skylights, the sunniest one usually fails first.
Safe checks first
What can you check yourself?
You can narrow down the cause without going on the roof.
- Note when the water appears: during rain only, or on cool or humid days without rain.
- Wipe the skylight glass and frame dry, then check again after the next rain or the next cool morning.
- Look closely for moisture between panes, which means a failed seal rather than a roof leak.
- From the ground, use binoculars to check for leaves or debris piled on the uphill side.
- Run the bathroom or kitchen fan more often and see if the moisture drops.
Take a close photo of where the water shows up each time. A pattern that stays in one corner points to one flashing piece, while water spread across the whole frame suggests a seal or condensation problem.
Tape a paper towel to the drywall right at the top of the skylight well. If it gets wet only during rain, the problem is almost certainly on the roof side, not condensation.
The pro visit
What happens during a skylight repair visit?
A typical skylight repair visit looks like this.
Interior check
The provider looks at the well, frame and glass and asks when the water appears.
Roof-side inspection
Curb, flashing, surrounding shingles and the uphill side are checked.
Water test if needed
Sections are tested one at a time to isolate the leak.
Repair or replace decision
You're told whether resealing, reflashing or a new unit makes sense, with reasons.
The repair
Flashing is replaced or resealed, shingles are reset, and the unit is repaired or swapped.
Final check
The area is inspected, and the skylight well is checked for wet drywall or stains that need attention.
Cost factors
What affects the cost of skylight repair?
Skylight repair pricing comes from the provider after an inspection. These factors matter most.
| Factor | Keeps cost lower | Pushes cost higher |
|---|---|---|
| Cause | Debris removal or resealing a flashing edge | New flashing kit or full unit replacement |
| Skylight type | Standard curb-mounted fixed unit | Venting, custom-size or tubular unit |
| Interior damage | Minor stain in the well | Wet drywall or mold in the well |
| Roof access | Low pitch, single story | Steep or high roof |
Urgency
When is a skylight leak urgent?
A skylight leak is urgent when the glass or dome is cracked or broken, when water is pouring through during a storm, or when water is dripping near light fixtures in the well.
If the dome is broken, the opening needs covering right away; emergency roof tarping or a fitted cover keeps rain out until repair.
Never step on or lean against a skylight on the roof. Many aren't built to hold a person's weight, and falls through skylights are a known, serious hazard.
Questions
Skylight Leak Repair questions from Cibolo homeowners
Is my skylight leaking or just condensation?
If moisture appears without rain, especially on cool or humid days, it's likely condensation. Water only during rain points to flashing or seals.
Can a leaking skylight be repaired instead of replaced?
Often, yes, when the flashing is the problem. Older units with failed seals are more often replaced.
Should flashing be replaced when a skylight is replaced?
Generally yes. Reusing old flashing with a new unit is a common cause of repeat leaks.
Why does my skylight leak only in heavy storms?
Heavy volume or wind-driven rain can overwhelm worn flashing or push water past a debris dam on the uphill side.
Can I remove a skylight instead of fixing it?
Yes, a skylight can be removed and the opening framed and roofed over. Ask the provider to price both options.
Do tubular skylights leak?
They can, usually at the flashing collar. They're generally simpler to reseal than large units.