Roof boots: the small part behind a lot of roof leaks
A roof boot seals the gap where a pipe comes up through your roof. It is cheap, it wears out before the shingles do, and it is a common source of leaks.
Most houses have a few pipes that stick up through the roof. They are plumbing vents. They let sewer gas out and let your drains flow. Each pipe makes a hole in the roof, and each hole needs a seal.
That seal is the roof boot, also called a pipe boot, vent boot or pipe flashing. It is a flat metal or plastic plate that sits under the shingles, with a flexible collar that hugs the pipe.
Why it matters
The building code requires flashing at every place something passes through the roof. In the International Residential Code, that is section R903.2. A roof boot is the flashing for a round pipe.
The collar is the weak point. A rubber collar sits in full sun all day. Over the years it dries, cracks and pulls away from the pipe. Then rain runs down the pipe and into the attic. The shingles around it can still look fine.
The main types
| Type | What it is | Good to know |
|---|---|---|
| Rubber (neoprene or EPDM) collar | Metal or plastic base with a rubber collar | The most common and the cheapest. The collar is the part that fails first. |
| Silicone collar | Same shape, silicone collar | Made to hold up better in sun and heat than standard rubber. |
| Lead boot | One piece of soft lead, folded over the top of the pipe | No rubber to crack. Squirrels sometimes chew it. |
| Split or retrofit boot | A boot that opens so it can go around a pipe | For repairs where the pipe cannot be taken out from the top. |
Boots are sold by pipe size. Measure the outside of the pipe before you buy one.
Signs your roof boot has failed
Check for these
- A water stain on the ceiling near a bathroom or kitchen Vent pipes run up from those rooms, so a boot leak shows up below them.
- Cracks or gaps in the collar Use binoculars from the ground. A collar that has pulled away from the pipe lets water in.
- Wet wood or a drip line on the pipe in the attic The pipe carries the water down. Look on a rainy day with a flashlight.
- Exposed nails or a lifted base The base should sit flat under the shingles above it and over the shingles below it.
Replace it yourself, or hire a roofer?
There is a slip-on rubber collar that fits over an old boot. It is a quick fix. A full new boot means lifting the shingles above it, sliding the new base under them, and nailing and sealing it. That is work on a roof, with a ladder and a fall risk.
Hire a roofer if the roof is steep, if the decking under the boot feels soft, or if water has been coming in for a while. Wet decking needs to be cut out and replaced, and that is not a boot job any more.
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International Code Council, 2021 International Residential Code, Chapter 9, section R903.2 (flashing): codes.iccsafe.org. Your local building department decides which code edition applies to you.
Questions homeowners actually ask
What is a roof boot?
A roof boot is the flashing that seals the hole where a plumbing vent pipe comes through the roof. It has a flat base under the shingles and a flexible collar around the pipe.
Is a pipe boot the same as a roof boot?
Yes. Roof boot, pipe boot, vent boot and pipe flashing all mean the same part.
Can I just put sealant around a cracked boot?
Sealant can stop a drip for a short time. It also cracks in the sun. Replacing the boot, or adding a slip-on collar, is the real fix.
Does a leaking pipe boot mean I need a new roof?
Usually not. A boot can be replaced on its own. You may need more work only if water has rotted the decking under it.