How do you fix a leaking roof vent pipe boot?
Short answer. Most leaking pipe boots have a cracked or shrunken rubber collar around the pipe, and the lasting fix is replacing the boot: lift the shingles above, remove the old flashing, slide a new boot over the pipe with its upper flange under the shingles, then renail and reseal. Slip-on repair collars and sealant can buy time but are temporary.
Confirm the boot is the source
- Stains on the ceiling or decking near a plumbing vent, often close to a bathroom or kitchen wall.
- From the attic, water tracks running down the vent pipe or a wet ring in the insulation around it.
- From the ground with binoculars or from the roof: a split, gapped, or sun cracked rubber collar, or a lifted flange.
- Nearby nail pops and damaged shingles, which can mimic a boot leak, should be ruled out too.
Replacing the boot
- Break the seal on the shingles above the boot and remove the nails holding the old flange.
- Slide the old boot up and off the pipe. If the pipe is short or damaged, a plumber may need to extend it.
- Slide the new boot down the pipe until the flange sits flat on the roof.
- Tuck the upper flange and sides under the shingles; the lower edge lies on top of the shingles below.
- Nail the flange where the shingles will cover the nail heads, then renail the shingles and seal the tabs.
Temporary options
- Slip-on repair collar: a new rubber sleeve that slides over the old boot. Fine as a stopgap on a roof you will replace soon.
- Sealant: a bead around a cracked collar may stop drips for a season, but it fails again in the sun.
Why boots fail early in Georgia
Rubber collars face intense UV and heat. They often crack well before the shingles around them wear out, which is why replacing every boot is standard during a reroof. Some homeowners choose lead or other longer lasting boots. See pipe boot leaks and common roof leak causes.