Skylights are all over Katy. Builders put them in thousands of homes in Cinco Ranch, Firethorne, and Seven Meadows, and most of those units are now 15 to 25 years old. That is right at the age where seals give up.
Texas heat does the damage. Summer sun bakes the rubber gaskets and plastic domes on your roof for months at a time. Seals shrink and split. Domes turn brittle. Then one hard rain sends a drip down the shaft, and the calls start.
Here is the good news. A leaking skylight rarely means the unit is dead. Most of the time the glass and frame are fine, and the failure sits in the metal and seals around them. We are a roof repair crew in Katy, and skylight leaks are a repair call we run every week. This guide walks through the same steps we use on the roof.
First, is it really a leak?
Not every drip under a skylight is a roof leak. Condensation fools a lot of homeowners, and it costs nothing to rule out.
Warm air inside your home rises. It hits the cool glass of the skylight and the moisture in that air turns to water on the inside pane. In humid Katy months this can drip off the shaft and land on the floor, just like a leak. The clues are simple. Condensation shows up on cool mornings with no rain at all. The glass fogs. The drips stop once the day warms up. Bathrooms and kitchens under a skylight make it worse, because showers and cooking load the air with moisture.
A real leak follows the weather. It shows during rain or right after it. It leaves stains on the shaft walls. Paint peels on one side of the shaft. And where the water shows tells the truth about where it gets in. Water at the top edge of the shaft points at the flashing on the high side of the unit. Water running down one side points at the side flashing or a split seal. A stain that spreads from the middle of the shaft with dry edges is worth a second look, because that pattern often traces back to condensation or a cracked dome.
Reading the water pattern is the first step on any leak call, skylight or not. It is the same skill we use when we track down leaks across a whole roof, which we cover in our guide to roof leak detection in Katy.
The 4 real causes
1. Flashing failure around the curb
This is the most common cause by a wide margin. Flashing is the metal kit that ties the skylight into the roof. It sits on the raised frame, called the curb, and the shingles weave into it. When that metal rusts, lifts at the edges, or loses its seal, rain slips under the shingles at the top of the unit and runs down the shaft. Most homeowners blame the glass. Most of the time, the metal around the glass failed first. Flashing is the top leak source on most roofs we climb, and our guide to roof flashing repair in Katy explains how that metal work fails and how it gets fixed.
2. Cracked dome and worn seals
Heat cooks the seals around the dome year after year. The rubber shrinks, hardens, and splits. Plastic domes get brittle in the sun and can crack from hail or a fallen branch. When this is the cause, water enters through the unit itself, not around it. You can often spot it from the ground with binoculars: a dome that looks yellowed, cloudy, or crazed with fine cracks is a dome at the end of its run.
3. Frame or curb rot on older units
Older skylights sit on wood curbs, and the frames on many older units are wood too. Wood that takes in water year after year starts to soften. Paint hides the damage for a long time. Once the wood goes soft, seals lose their grip, and each new fix holds for a shorter run than the last. If a skylight has leaked on and off for years, rot is high on the list.
4. Poor install with no proper flashing kit
Some units were never flashed right in the first place. The builder skipped the proper flashing kit and face sealed the joint with caulk alone. Caulk is not a system. It is a bead of goo that the Texas sun kills in a few years. These skylights leak early, and they keep leaking until the flashing is torn out and done right.
How we find which one you have
Guessing leads to caulk on the wrong seam. We test instead, in a set order.
Read the pattern first. We start inside and study the shaft. The spot, the shape, and the side of the stain tell us which edge of the unit to test first. A stain that starts high on the shaft points up. A stain low on one side points to that side.
Run a hose test. One of us stays inside and watches the shaft. The other runs water on the roof in stages. Low on the roof below the unit first. Then up the sides. Then over the top edge last. The leak shows itself at one stage, and that stage names the cause. Flooding the whole roof at once tells you nothing, because the water can come from any edge at all.
Check the attic. Where the shaft passes through attic space, we look at the wood and insulation around it. Wet insulation and dark, soft wood confirm how long the leak has run and whether rot is part of the job.
Only after those three steps do we quote the fix. By then we know if you need a reseal, a flashing repair, or a hard talk about the unit itself.
The fixes and what they cost
Reseal and minor work: $150 to $500. Fresh sealant at the dome and frame joints, small flashing touch ups, and a few shingles reset around the unit. This fits seal wear where the flashing and the wood are still sound. It is the fix most Katy skylights need.
Flashing repair: $150 to $1,500. We lift the shingles around the unit, repair or swap the failed metal, and seal the curb the right way. The price turns on roof pitch and how much shingle work it takes to reach the metal.
Full reflash: top of the flashing range. Old metal out. New flashing kit in. Shingles woven back in the right order. This is the fix for poor installs and for metal that has rusted through. It costs the most of the repair options, and it is the one that ends repeat leaks.
A unit at the end of its life. If the dome is cracked through or the frame has rotted out, repair money is wasted money. A new unit is quoted per home, after we measure the curb and check the shaft. Any roofer who quotes you a skylight unit price over the phone, sight unseen, is guessing with your money.
For the wider picture of what leak work runs across a roof, see our roof leak repair cost guide for Texas.
Repair the skylight or replace the unit?
Four tests settle it.
Age. Domes and seals age out first. A unit past 15 to 20 years old with a brittle dome is close to the end, even if the frame still looks fine.
Dome condition. Cracks, fog trapped between the panes, and yellowed plastic all mean the unit itself is failing. No flashing repair fixes a dead dome.
Leak history. One leak at the flashing is a repair. The third leak at the frame in two years is the unit telling you it is done.
Where the failure sits. If the unit is sound and only the metal failed, repair wins every time. That is the most common case we see in Katy, and it is why we test before we quote.
Our stance is the same here as on every job. If a reseal or a reflash fixes it, we will tell you that, even though a new unit pays us more.
Call (281) 677-8586
Skylight leak questions
How much does it cost to fix a leaking skylight?
Most Katy skylight leaks cost $150 to $1,500 to fix. Reseals and minor work run $150 to $500. Flashing repair runs $150 to $1,500, with a full reflash at the top of the range. If the unit itself has failed, a new unit is quoted per home after an inspection.
Can a leaking skylight be repaired?
Yes, in most cases. Flashing failures and worn seals repair well, and they cause most skylight leaks. Repair stops making sense when the dome is cracked through or the frame and curb have rotted out.
What is the most common cause of skylight leakage?
Failed flashing around the curb. The metal kit that ties the unit into the roof rusts, lifts, or loses its seal, and rain slips under the shingles at the top edge of the unit.
Where do most skylights usually leak?
At the top edge and along the sides, right where the flashing meets the roof. Leaks through the glass itself are rare and point to a cracked dome.
Is the water on my skylight a leak or condensation?
Check the timing. Water that shows on cool mornings with no rain, on glass that fogs, is condensation from indoor air. Water that shows during rain and leaves stains on the shaft walls is a leak. The pattern tells you which one you have.
Should I repair or replace my skylight?
Repair it if the dome and frame are sound and the failure is in the flashing or seals. Replace the unit if the dome is cracked or fogged, the frame is soft with rot, or leaks at the frame keep coming back after sound repairs.
Call (281) 677-8586
Lines open 7 AM to 9 PM.
That is how we handle roof repair in Katy. Find the real cause, fix that part, and show you the photos so you can see it too.