Why Is My Skylight Leaking? 3 Causes

Why is my skylight leaking?

Published October 13, 2026 · John Beal, Owner, John Beal Roofing

Usually it's one of three things: failed flashing around the frame, a worn-out seal, or condensation, which isn't a leak at all. Get the whole frame checked, not just the glass.

A skylight brings in great light, right up until the day you see a water stain on the ceiling next to it, or drops collecting on the frame. Before you assume the worst, it helps to know there are really only three usual suspects, and one of them isn't a leak at all.

Cause one: failed flashing around the frame

A skylight is a hole in your roof, and flashing is what keeps it from acting like one. It's the metal and membrane that wraps around the frame and steers water around the skylight and back onto the shingles. Over time, flashing can crack, pull loose, or rust. Sometimes it was never installed right in the first place. When it fails, rain runs straight down the sides of the frame and into your ceiling. This is the most common cause we find.

Cause two: a worn-out seal

The seal between the glass and the frame doesn't last forever. Years of summer heat and winter cold make it shrink, crack and pull away. Once it does, water can seep in around the glass itself. You'll often see it at the edges of the glass or in the corners of the frame after a good rain.

Cause three: condensation, which isn't a leak at all

On a cold morning, warm, humid air inside your house hits the cold glass of the skylight and turns to water, just like a glass of iced tea sweating on a summer day. Those drops can run down and drip, and it looks exactly like a leak. The giveaway is timing. If it happens on cold, dry days with no rain, it's probably condensation. If it shows up during or after storms, it's water getting in from outside.

Get the whole frame checked, not just the glass

A lot of skylight "repairs" are a bead of caulk around the glass. That might hold for a little while, but if the problem is the flashing, the water just finds another path. The only real fix is finding the actual cause, and that means looking at the entire frame, the flashing, and the shingles around it, not just the part you can see from inside.

What to do in the meantime

Put a towel or bucket under the drip, move anything valuable out of the way, and take photos of the stain and when it shows up. Don't climb onto the roof to look yourself. Skylights and wet shingles are a bad combination.

When we come out

We check the flashing, the seal, the shingles around the skylight and the ceiling below. Then we tell you straight whether it's a repair, a reflash, or condensation you can handle with better ventilation. We answer the phone 24/7, so if it's dripping during a storm, call.

What John says in the video

Transcript: Why is my skylight leaking? Usually it's one of three things. One: failed flashing around the frame. Two: a worn-out seal. Three: condensation. That's not a leak at all. Get the whole frame checked, not just the glass. Call me. 1-800-JOHN-BEAL.

Frequently asked questions

How do I tell a skylight leak from condensation?

Condensation tends to show up on the inside of the glass when it is cold outside and humid inside, often without any rain. A leak usually shows up during or after rain, often at the edges of the frame or on the ceiling around it.

Can I fix a leaking skylight with caulk?

Caulk might stop a drip for a while, but if the flashing around the frame has failed, the water will find another way in. The real fix is correcting the cause.

What is skylight flashing?

It is the metal and membrane around the skylight frame that directs water around it and onto the roof. When it cracks, loosens or was installed wrong, water gets in around the frame.

Should I replace my skylight when I replace my roof?

It is a good time to look at it, because the flashing around the skylight is being redone anyway. We will tell you whether the skylight itself is still in good shape.

Who can find out why my skylight is leaking?

We can. We check the whole frame and the flashing, not just the glass, and tell you what is really going on. Call 1-800-JOHN-BEAL, answered 24/7.