How to install pipe boot for roof vent?

Old 08-26-07, 09:12 AM
Thread Starter
Join Date: Dec 2004
Posts: 16
Upvotes: 0
Received 0 Upvotes on 0 Posts
How to install pipe boot for roof vent?

I have a short pipe sticking up through my roof - I'm pretty sure it is to vent inside plumbing. It has a rubber boot around it and shingles go over top. I think rain water is leaking past the boot, running down the exhaust pipe and I just happen to have a bathroom exhaust fan directly below. I've had dripping out the exhaust vent the past couple of heavy rains.

I was up on the roof. My boot is old and cracked. I have a replacement from Lowes but am worried I'll tear up my shingles getting the old one out. Is there a trick to doing this? I've already had a small amount of water damage to my bathroom celing because of this so I need to fix it pronto. How do I get the new one on? The 20 year old shingles act like they don't want to bend too much.
Old 08-26-07, 01:37 PM
XSleeper's Avatar
Group Moderator
Join Date: Dec 2004
Posts: 27,023
Received 1,900 Upvotes on 1,706 Posts
It's definately a trick to try to get old sealed shingles apart without destroying them. Using a hammer on a flat bar and tapping under the tabs of the shingles to break the tar seal is the first step. If you can do that without ripping holes in the tabs, you're well on your way. You only need to remove the shingles that overlap the pipe boot on the sides and top of the boot. It will probably be at least 2 rows of shingles... maybe 3 or 4 individual shingles at the most. The shingles that are under the boot do not need to come off.

Once the shingles are removed, the boot will come off, the new one will go on. It's a good idea to flash the top of the boot under the felt... or add a new piece of felt over it, and tuck that piece of felt under an existing seam in the felt.

Then you shingle around it... cutting your shingles around the curve of the boot until the fit nicely... leaving perhaps 1/2" around the flange for drainage. Some like to run a bead of sealant on the perimeter of the boot, before laying a shingle into the sealant (as added insurance against leaks).

You don't usually want to reuse the shingles you have removed, because of the nail holes in them. But if you do reuse them you'll need to nail in a different spot and use plenty of roof sealant to seal up the old holes. I would highly recommend you repair the patch with new shingles. They won't match perfectly but hopefully this repair will get you by until the roof gets redone- which if they are 20 yrs old... is not far off.

Thread Tools
Search this Thread
Ask a Question
Question Title:
Your question will be posted in: