How do you replace a pipe boot, and how much does it cost?
Short answer. Release the shingles above the boot, pull its nails, slide the old boot off the pipe, slide on a new boot of the same size with the upper flange under the shingles and the lower flange over them, nail the top corners, and reseal the shingles. Hired out, a single boot replacement usually runs a few hundred dollars depending on pitch, height and access; the part itself is inexpensive.
Step by step
- Measure the pipe. Most plumbing vents are 1.5, 2 or 3 inch pipe, and the boot must match.
- Use a flat bar to break the seal on the shingles covering the upper half of the old boot, and pull the nails holding its flange.
- Slide the old boot up and off. If it is stuck, cut it away carefully without nicking the pipe.
- Slide the new boot down until the collar grips the pipe snugly. The upper half of the flange goes under the shingles above; the lower half lies on top of the shingles below.
- Nail only the upper corners, where shingles will cover the nails, and seal the heads.
- Press the shingles back down and hand-seal them with dabs of roofing cement.
What drives the cost
- Pitch and height: a steep two-story roof needs more safety setup and time.
- Boot type: an all-silicone or lead boot costs more than a standard rubber collar but lasts longer.
- Damage underneath: soft decking around a boot that leaked for months adds labor.
- How many: replacing every boot in one visit costs less per boot than one at a time.
Rubber collars commonly crack long before the shingles wear out under Georgia sun, so check them every few years with binoculars. During a full replacement, boots should always be replaced, never reused. More in pipe boot leaks.