How do you replace a pipe boot on a shingle roof?
Short answer. Measure the pipe and buy a boot of the same size, then on a mild day break the seal on the shingles above the old boot, pull the nails holding it, slide it up and off the pipe, and slide the new boot down with its upper flange under the shingles above and its lower flange on top of the shingles below. Nail the upper corners where shingles will cover them, reseal the shingles, and check that the collar fits snugly with no nail heads exposed.
Tools and materials
- A new boot sized to the pipe's outside diameter, commonly 1.5, 2, 3 or 4 inches.
- A flat pry bar, hammer, utility knife and roofing nails.
- Asphalt roofing cement or shingle sealant.
- Fall protection, and a helper at the ladder.
Step by step
- Pick the right day. Mild and dry. Cold shingles crack when lifted; hot ones tear and scuff.
- Unseal the shingles above. Slide the flat bar under the courses above the boot to break the sealant strip, working gently.
- Pull the nails holding the old boot's upper flange, usually hidden under those shingles.
- Remove the old boot. Slide it up and off the pipe, or cut it off if it is stuck.
- Check the deck. Probe around the hole for soft wood and replace damaged decking before going on.
- Slide the new boot on. The upper flange goes under the shingles above, the lower flange lies on the shingles below, and the collar sits snug around the pipe.
- Nail it at the upper corners, where the shingles above will cover the nails. Never nail through the exposed lower flange.
- Reseal. Put dabs of roofing cement under the lifted tabs and press them down.
When to stop and call
- The roof is steep, high or wet.
- Shingles crack when you try to lift them.
- The pipe is a hot metal flue from a furnace or water heater, which needs metal flashing and a storm collar, not a rubber boot.
- The deck around the pipe is soft.
Choose a boot with a metal base and a UV-resistant collar for longer life in Georgia sun. See pipe boot leaks and common roof leak causes.