How do you replace a roof vent boot, step by step?
Short answer. To replace a vent boot, break the seal on the shingles above the old boot, pull the nails holding its flange, slide the old boot up and off the pipe, then slide a new boot of the same pipe size down over the pipe with its upper flange tucked under the shingles above and its lower flange over the shingles below. Nail the flange where the shingles above will cover the nails, reseal the shingles, and check the collar fits snug on the pipe.
Tools and parts
- A replacement boot sized to the pipe, commonly 1.5, 2, 3 or 4 inches.
- A flat bar or shingle remover, hammer, roofing nails and roofing sealant.
- Fall protection. Do not work on a wet or steep roof.
Steps
- Break the seal: slide a flat bar under the shingles above and beside the boot to free the adhesive strip. Mild weather makes this easier; hot shingles tear and cold ones crack.
- Pull the nails that hold the old flange, working under the shingles.
- Remove the old boot by sliding it up and off the pipe.
- Check the pipe: if it is cracked or the top is broken, cut it clean or have it repaired.
- Install the new boot: slide it down the pipe until the base sits flat on the deck. The upper flange goes under the shingles above; the lower edge laps over the shingles below.
- Nail the upper corners and sides of the flange where the shingles above will cover the nails. Do not leave exposed nails on the lower flange.
- Reseal the loosened shingles with dabs of sealant and press them down.
Check your work
- The collar should grip the pipe without tears.
- The flange should lie flat, with no shingle lifted above it.
- After the next rain, look in the attic around the pipe.
See pipe boot leaks and roof flashing explained.