How to Install a Roof Boot on a Metal Roof

a chimney vent on a roof
  • 3-6 hours
  • Intermediate
  • 80-300
What You'll Need
Multi-size pipe flashing
Silicone sealant
Sheet metal screws
6-inch knife
Drill or screwdriver

There are a number of easy-to-install roof boots available at your local home improvement store. However, these boots are designed for asphalt or rubber roofs and won’t be effective on a metal roof. This doesn’t mean that you can’t add a roof boot to your metal roof, it just means that you have to use a different type of device.

To offer water protection around the pipe vents on a metal roof, you will have to use a pipe flashing created specifically for the corrugated surface of a metal roof. The flashing will be fitted with an aluminum flange. A roof boot for a metal roof will also have a heat rating. Look for one that is heat rated to at least 212 degrees F. Though you should be able to find a metal roof pipe flashing at your local home improvement store, you will probably find a larger selection at a roofing supply store.

Step 1—Clean the Pipe

The vent pipe needs to be clean before you can install a roof boot. There may be old caulk and sealant on the pipe. Use your 6-inch knife to remove the old debris. The better you clean the pipe, the better the seal you will get from your roof boot. It is important that the pipe be free of any sharp material because you don’t want to damage the lip of the new roof boot.

Step 2—Apply Silicone Sealant

A silicone sealant needs to be applied to the area of the roof where the aluminum flange will be attached. You will also add a heavy bead of sealant to the aluminum flange itself. It is important that you use enough sealant so that the boot will fit securely. This sealant is going to be what keeps water from getting in under the flange.

Step 3—Fit the Roof Boot

The opening on the top of the boot will be considerably smaller than the diameter of the pipe. This is the correct fit. The pipe will stretch the boot’s opening and create a snug, watertight seal. Make sure that you measure the diameter of the pipe before you purchase the boot so that you can ensure a perfect fit. Otherwise, you aren’t going to be able to guarantee a watertight seal.

Push the boot over the top of the pipe and push down to the bottom. Make sure that the bottom of the boot is flush with the top of the corrugated roof. The aluminum flange on the boot should be pressed down into the large grooves of the roof. Make sure that there is an adequate sealant to secure the boot in the proper position. Take the time to work the aluminum into place just right. Ideally, you want the aluminum to be tight and flush against every groove in the roof.

Step 4—Screw Boot in Place

Once the boot is secured with the sealant, screw it in place with sheet metal screws.

There you have it! You have placed a roof boot on your metal roof to offer another level of protection from water penetration.