Why pipe boots crack so often in San Antonio
A standard pipe boot is a metal or plastic base with a rubber collar that hugs the vent pipe. The base slides under the shingles above and over the shingles below. The rubber collar is what keeps water from running down the pipe into the attic, and it's the weak point.
Rubber breaks down under UV and heat. On a south or west slope in San Antonio, a collar can start to crack and shrink after several summers, often long before the shingles around it need replacing. Once there's a gap between rubber and pipe, every rain sends a little water down the pipe and onto the decking or drywall.
These leaks are often slow and easy to miss. You might see a small stain on a bathroom or hallway ceiling, or nothing at all until the drywall sags. If you've had a leak traced to a pipe, our ceiling stain and leak tracing page explains how we confirm the source.
Which pipe boot should replace the old one?
We match the boot to the pipe and the roof. For most homes, a boot with a UV-resistant silicone or EPDM collar lasts longer than basic rubber. Lead boots, which are folded over the top of the pipe, hold up well and don't crack, though they can be damaged by squirrels chewing on the soft metal.
On metal roofs, pipe flashings use a flexible base that's sealed and screwed to the panel ribs. On tile roofs, the boot sits under the tile with a lead or soft metal skirt formed over the tile profile above it. Each needs a different method, so tell us your roof type when you call.
- Silicone or EPDM collars for longer UV life on shingle roofs.
- Lead boots that fold over the pipe top and don't crack in sun.
- Flexible retrofit flashings for metal panel roofs.
- Lead-skirted boots formed to fit under clay and concrete tile.
Turbines, box vents and exhaust caps
Roof vents fail in their own ways. Turbine vents seize up as bearings wear, and a stuck turbine can wobble loose or let wind-driven rain in. Box vents, the square low-profile kind, dent in hail and rust at the seams. Bathroom and kitchen exhaust caps lose their dampers or come loose at the base.
We replace damaged vents with the same style or with a better match for your attic. If your attic stays extremely hot or vents seem mismatched, that's a ventilation design question rather than a simple repair. Our intake and exhaust balancing page covers how we size and lay out a balanced system.
Hail often dents vents even when the shingles look fine. A dented vent isn't always leaking, but it's good evidence of hail size. If a storm just passed through, a post-storm roof report will record vent damage along with the rest of the roof. That record is useful later if the dents turn out to matter.
How a proper pipe boot replacement is done
We carefully break the seal on the shingles above the old boot and lift them without cracking. The old boot is removed, nails are pulled and the opening is checked for soft decking. The new boot slides under the upper shingles and over the lower ones so water flows across it, not behind it.
New nails go in where the shingles above will cover them, and those shingles are sealed back down by hand. On exhaust vents, we check that the duct actually connects to the vent from inside the attic. A disconnected bath fan duct can dump moist air into the attic and look like a leak.
Should you replace all the pipe boots at once?
If one boot has cracked from sun, the others on the same roof are usually close behind, especially on the same slope. Replacing all of them in one visit costs less than separate trips, and it removes one of the most common leak sources for years.
We'll photograph each boot and vent so you can see their condition. If the rest are still flexible and tight, we'll tell you so. Boots and vents are also checked as part of our seasonal roof maintenance visit, which catches cracking early. Spring is a good time, before the summer sun does its worst on rubber that's already brittle.
Abandoned vents and old satellite holes
Many roofs have openings that no longer do anything: an old exhaust cap from a removed range hood, an unused vent pipe, or lag holes from a satellite dish taken down years ago. Each one is a potential leak point with no purpose. They're easy to forget because nobody uses them, which is exactly why they go unchecked for years.
We can remove abandoned vents, deck over the opening and shingle it to match, so there's one fewer penetration to worry about. Satellite mount holes get filled and covered with new shingles instead of a dab of caulk that will dry and crack. That's a small job when we're already on the roof for a boot.
