How to Repair a Roof Boot

What You'll Need
Rain and repair pipe collar
6-inch knife
Silicone caulk
Caulk gun

Most times, roof boots are built into the flashing that covers pipe vents. They are designed to keep water from entering the building by creating a water tight seal around the pipe. Roof boots are built to maintain their water tight seal even in the most extreme weather conditions. However, over time they will begin to tear and gap. When this happens, there is a chance that water will enter your home through the damaged roof boot. It is imperative at this point that you repair the roof boot.

There are a number of different methods for repairing a roof boot. You can cover the lip of the damaged boot in mastic or silicone caulk. You can also replace the entire flashing around the pipe. However, replacing the entire flashing can be quite involved and may require the application of new shingles. The best way for a do-it-yourselfer to repair a roof boot is to seal the existing boot and apply a new rain and repair pipe collar. You will need only a few materials and they will all be available at your local home improvement store.  

Step 1—Clean Pipe and Boot

You’ll need your 6-inch knife to make sure that there isn’t any old sealant or caulk around the boot. Take the extra time to clean the pipe and boot well. You can only insure a tight seal if you remove the old material. The old caulk will be prone to cracking and you want to make sure that the new seal is tight.

Step 2—Apply Exterior Caulk

The area of the boot that will need to be repaired is going to be lip that hugs the diameter of the pipe. With a careful inspection, you’ll probably find cracks of varying sizes or gaps. These are the spots were water is gaining access to the inside of your home. Apply a liberal amount of heavy-duty exterior caulk to the lip of the boot. You want to make sure that you have sealed any cracks or gaps. You may want to use a silicone or metal roller to flatten the gaps and ensure a superior hold.

Step 3—Fit Collar to Pipe

The rain and repair collar is going to be placed over top of the existing boot. Make sure that you select a collar in the correct size. The opening on the top of the collar will be smaller than the pipe itself. This will make sure that the fit is snug and that the collar creates a water-tight environment. Stretch the collar on to the top of the pipe.

Step 4—Secure at Base of Pipe

The rain and repair collar need to be as far down on the pipe as possible. Grab the collar from the top and pull it down as far as it goes.  It is important that the pipe is clean, so that the lip of the collar is not damaged from old, hardened materials.

That’s it. Your roof pipe is now repaired and your home is water tight once again.