Skylight Leaking in Austin? How to Tell a Leak From Condensation and What Fixes It
When a skylight leaks, the first place to check is the flashing where it meets the roof, not the glass. Water gets in where the skylight meets the roof, runs down the light well, and shows up as a stain at the bottom corners of the opening. Before anyone touches the roof, rule out condensation, because moisture on the inside of the glass can look a lot like a leak.
Is my skylight leaking, or is it condensation?
Start with timing and location. These questions sort out most cases:
Did it show up during or right after rain? A stain that appears or grows after a storm points to a roof leak. Water on dry, cool mornings is more likely condensation.
Where is the water? Beads across the inside of the glass often mean condensation. Stains or peeling paint in the light well, or wet spots at the lower corners of the opening, point to a leak.
Is there fog between the panes? Haze trapped between two layers of glass means the seal on the glass unit has failed. That isn't a roof leak, but the unit is wearing out.
Does it open? Make sure it's fully closed. Worn gaskets on vented skylights can let water in.
VELUX, a skylight maker, explains that warm, moist air rises to the ceiling and meets the cooler glass, so condensation shows up on skylights first. Exhaust fans and ceiling fans help. If the water stops when the humidity drops, the roof probably isn't the problem.
Where do skylights leak on Austin roofs?
The U.S. Department of Energy's Building America guide calls skylights one of the most common ways water gets into a home. On Central Texas roofs, a skylight leak usually starts here:
The flashing. On a shingle roof, a metal piece runs across the bottom, step flashing is woven in with each row of shingles up the sides, and head flashing covers the top. If a piece is missing, bent or rusted, water gets behind it.
The top of the skylight. Leaves, twigs and grit collect on the uphill side. Water backs up there and finds any gap. Shingles above the skylight should stop about an inch short so water has a channel to run around it.
Old caulk and roof cement. Home inspection groups call caulk on a skylight a temporary repair at best. It dries and cracks in the sun. Lots of it usually means the skylight has leaked before.
The curb. Many skylights sit on a wood frame called a curb. Slow leaks can rot it without showing much inside.
The skylight itself. Water can come through frame joints or cracked glazing.
Austin is hard on all of it. NOAA's 1991–2020 averages for Camp Mabry show about 123 days a year at 90°F or hotter, which bakes sealant and plastic domes. NOAA's storm records also list 121 reports of hail an inch or larger in Travis County and 163 in Williamson County from 2016 through 2025. An old plastic dome that has turned brittle in the sun can crack in hail or when a branch hits it.
What can I check myself without getting on the roof?
Stay off the roof, especially if it's wet or steep. You can still learn a lot from inside and from the ground:
Look up the light well with a flashlight. A stain at a bottom corner often means water is getting in at the side or bottom flashing.
Check the attic if you can reach the back of the well safely. Dark staining or soft wood around the opening means water has been getting in for a while.
Look from the ground with binoculars or a phone zoom. Watch for leaves piled above the skylight, smears of sealant, a cracked or yellowed dome, or bent flashing.
Take dated photos. Pictures after each rain show whether the stain is growing.
Skip the garden hose test. The Building America guide warns that spraying too hard, or upward at seals, can cause leaks that never happen in real rain.
How do we fix a leaking skylight?
At a free roof inspection, Vantage Roofing checks the skylight from the roof, the attic and the room below: flashing on all four sides, the curb, the glazing and the shingles above it. Then we show you photos and explain the options:
Re-flash it. If the skylight is in good shape, we cut back the shingles around it, add self-adhering membrane, and install new sill, step and head flashing in order, so each layer sheds water over the one below. This is the usual fix when the skylight itself is sound.
Fix the wood. If the curb or the roof deck around the opening is soft, we replace that wood while the area is open.
Replace the skylight. A cracked or yellowed dome, glass fogged between the panes, or a leaking frame means it's time for a new unit with a flashing kit made for it.
The flashing has to match the roof. A shingle kit doesn't belong on a tile or metal roof. The International Residential Code also requires a skylight on a low-slope roof (under 3 in 12) to sit on a curb at least 4 inches high unless the manufacturer says otherwise. What we avoid is another layer of caulk.
Should I replace my skylight when I replace my roof?
Often, but not always. The Building America guide says to inspect every skylight during a re-roof and keep it only if it's in good shape and fairly new. Either way, it gets new flashing tied into the new underlayment and shingles. Old flashing on a new roof is how a new roof ends up with an old leak.
If the shingles are near the end, it's usually smarter to do both at once so the area is only opened up one time.
Repair, replace, or leave it alone?
A re-flash or repair is the right call when the skylight itself is sound and the water is coming in around it.
A new skylight makes sense when the glazing is cracked, cloudy or fogged, or the frame leaks.
Sometimes nothing on the roof needs work. If the attic is dry, the flashing is tight, and the water only shows up on humid mornings, it's condensation. We'll tell you that, so you can work on airflow and humidity in the room instead.
Schedule a free skylight and roof inspection
Call (737) 383-1768 to schedule a free roof inspection in Austin, Round Rock, Georgetown or nearby. We'll check the skylight flashing, curb and glass, show you photos, and tell you honestly whether it needs a repair, a replacement, or nothing at all. Vantage Roofing backs its work with a 10-year workmanship warranty on full replacements and up to 1 year on service repairs. You can also reach us through our contact page or read our guide to a roof leak after rain.
Frequently asked questions
Can you come look at my skylight first before telling me what's wrong?
Yes, and that's the right way to start. Vantage Roofing comes out for a free roof inspection and checks the skylight from the roof, the attic and the room below. We take photos of the flashing, curb and glass so you can see what we see. You get a written estimate before any work starts.
My skylight only drips on some mornings, not when it rains. Is that a leak?
Probably not. Water that shows up on cool or humid mornings, with no rain, is usually condensation forming on the glass from moist indoor air. Run the bathroom or kitchen exhaust fan, use a ceiling fan, and see if it stops. If you also see stains that grow after storms, there may be a leak too, and an inspection will sort out which is which.
Can I just put caulk around my skylight to stop the leak?
We don't recommend it. Caulk or roof cement on a skylight is a short-term patch. It dries out and cracks in Austin's sun, and it can hide the real problem, which is usually flashing that's missing, damaged or installed in the wrong order. On plastic domes, sealant at the edge can stress the dome as it expands in the heat. Re-flashing is the lasting fix.
How fast can someone come out for a leaking skylight?
Call (737) 383-1768 and we'll set up a time that works for you. If water is dripping into the room right now, tell us when you call, and put a bucket and towels under the drip until we get there. If it's an older stain that only grows after rain, we'll schedule a regular inspection.
Do I need a whole new roof because my skylight leaks?
Usually not. A skylight leak is a contained problem, and re-flashing or replacing the skylight fixes it when the shingles and deck around it are in good shape. A full replacement only makes sense if the rest of the roof is worn out or water has damaged a wide area of the deck. We'll show you photos before you decide.
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