Usually because the pipe boot failed. A pipe boot is the flashing that seals the hole where a plumbing vent pipe comes through the roof. Its rubber collar dries out and cracks as it ages, or the boot may have been put on wrong. Replacing the boot is usually a small repair, as long as the wood around it is still sound.
Your drains need air to flow, so plumbing vent pipes run up through the roof. That makes each one a hole that has to stay sealed for years of sun, heat and storms. Here is how to tell if a vent pipe is your leak, what the fix involves, and why a tube of sealant is not it.
The vent pipe on your roof is part of your plumbing. It lets air into the drain lines so they flow, and it lets sewer gas out above the roof instead of inside the house. Florida's plumbing code has it end at least 6 inches above the roof. Where the pipe passes through, a flashing called a pipe boot seals the opening around it.
On a shingle roof, a pipe boot is usually a flat flashing base with a rubber or plastic collar that fits snugly around the pipe. Some are lead. The base is tucked under the shingles above the pipe and laid over the shingles below it, so water running down the roof stays on top. On a tile roof, Florida's tile installation manual calls for a lead skirt or a flexible flashing with a base at least 18 by 18 inches, worked into the rows of tile.
Florida's building code requires flashing around openings in the roof, and says vent pipe flashing on a shingle roof has to follow the shingle maker's instructions.
Vent pipes usually come up through the roof near the rooms they serve, so a ceiling stain close to plumbing is a strong hint. Water can still run along the framing before it drips, so look for the other signs too.
With a flashlight, look where the pipe passes through the roof deck. Dark, stained wood or damp insulation in a ring around the pipe points straight at the boot.
Drips or water marks running down the outside of the pipe below the roof deck mean the water is getting in at the top, around the collar.
From the ground, binoculars or a phone camera zoomed in can show a split collar, a gap between the collar and the pipe, or nail heads lifting at the base. There is no need to climb up to look.
The collar takes the hardest hit. As a boot ages, the collar dries out and cracks, and once it splits, rain runs down the pipe and into the attic. ARMA's roofing manual suggests checking vent flashing for cracks once a year, which you can do from the ground with a zoomed-in photo.
The base can fail too. It has to be lapped the right way: its lower edge over the shingles below, the shingles at the sides and top over the base, and the nails at least 2 inches from the pipe. A base set on top of the shingles above it, or nails left exposed, gives water a way under the roofing.
And sealant is not a repair. InterNACHI calls a vent that relies on sealant alone an improper installation, and Florida's hurricane retrofit guide calls sealant a poor long-term fix on a roof that takes this much sun. A cracked or loose boot should be replaced, not caulked.
The roof deck around the pipe is checked from the attic and from the roof. Soft or stained plywood around the hole gets replaced while the area is open, because a new boot on rotten wood will not hold.
The shingles above the pipe are lifted with care, the nails come out, and the old boot slides up and off the pipe.
The new boot goes over the pipe with its lower edge over the shingles below, and the shingles at the sides and above lapped over its base. The nails stay at least 2 inches from the pipe, under the shingles above, so water stays on top of everything.
Any nail heads left exposed are sealed, the shingles are pressed back down, and the finished work is photographed so you can see what was done.
The tiles around the pipe are lifted, the flashing is redone, and the tiles go back in place. Florida's tile manual calls for a lead skirt or a flexible flashing with a base at least 18 by 18 inches, worked into the rows of tile. It takes more care, because tile cracks when it is walked on the wrong way. Why walking on tile is tricky.
If your roof is only a few years old and the vent pipe leaks, ask the company that installed it to check how the boot was put in. Look in your contract for their workmanship warranty and call them first. If they will not come back, or the fix does not hold, our guide to a new roof that is already leaking covers your next steps, and we are glad to take a look.
Then the roof may not be the problem. A bathroom exhaust fan duct or the air conditioner drain line in the attic can drip near a ceiling with no rain at all. Our guide to ceiling water stains helps tell a roof leak from a plumbing or AC leak.
"He came out today to repair a hole in our roof, and from start to finish, the experience was exceptional. ... What impressed me most was that he took the time to assess the situation honestly and didn't try to upsell me or recommend work that wasn't necessary."Nicole M.Roof repair, Florida Gulf Coast
It is the flashing that seals the hole where a plumbing vent pipe comes through the roof. On a shingle roof it is usually a flat base with a rubber or plastic collar that fits snugly around the pipe. Some are lead.
Look for a stain near a bathroom, kitchen or laundry room, and check the attic for wet wood or insulation in a ring around the pipe. Water running down the outside of the pipe below the roof deck is a strong sign.
It can slow a drip for a short time, but it does not last. InterNACHI calls a vent that relies on sealant alone an improper installation. A cracked or loose boot should be replaced.
A small crack may let in so little water in a light rain that nobody notices, and enough in a downpour to stain the ceiling. Our guide on leaks that only happen in heavy rain covers the other causes.
Usually not, if it is caught early. Replacing the boot is a small job. It grows when water has been getting in long enough to rot the roof deck around the pipe, which is why it is worth fixing soon.
Yes. Call (941) 896-7793 or text a photo to (941) 345-0072. If you can zoom in on the pipe from the ground, send that photo too.
A zoomed-in photo of the pipe from the ground, or of the stain inside, helps us tell you what we are likely looking at.
Leave your name and number. We typically call back the same day during business hours. Consent to texts is not required.
