What is a zipper boot on a metal roof?
Why retrofit boots exist
A standard pipe boot slides down over the pipe from the top. On a metal roof that is easy during new construction but hard later, when the pipe is a flue, a vent stack tied into plumbing, or a solar or satellite cable. A zipper boot opens along one side, wraps the pipe, and closes with an interlocking seam that is sealed as the instructions direct.
How the base seals
Like other metal roof pipe flashings, the boot has a flexible base, often aluminum-reinforced rubber, that can be pressed to follow the panel's ribs. Sealant goes under the base, and screws with sealing washers fasten it through the panel around the perimeter.
When to use one
- Replacing a cracked or sun-rotted boot on an existing pipe.
- Adding a cable or conduit penetration through an installed roof.
- Flues or stacks that cannot be cut or lifted.
Installation tips
- Size the boot to the pipe diameter and trim the cone for a snug fit.
- Orient the zipper seam as the manufacturer directs, usually away from the uphill water flow.
- Position the base so water flows around it rather than into a dammed rib.
- Use high-temperature boots for hot flues and follow clearance rules.
- Clean the panel and use sealant compatible with its finish.
Limits
A zipper seam is one more joint to maintain. When a roof is being replaced, a one-piece boot slid over the pipe is the more durable choice. Rubber boots of any type age in Georgia sun, so check them during routine inspections.
See pipe boot leaks and metal roofing in Georgia.