Plumbing vent pipes on house roofs are covered with a metal square of flashing and sealed with silicone caulking.
How to seal reaeal pipe boot on roof.
Vent pipes are roof penetrations so holes are created.
Roof water damage repair small hole in roof leaking metal roof how to stop.
How to seal a plumbing vent pipe on the roof.
The flashing of the vent pipes.
As mentioned there s a rubber boot that serves as a seal to prevent water from leaking in.
On the boots if you have metal roof jacks with rubber boot seals on top with many models the rubber seals can be popped off and replaced without removing the metal part and there are also slip over boots that can just nestle down over the existing damaged boot and overlap the top of the jack but contractor would have to look at it and see then go get parts so if using a contractor.
Even if the hole matches the size of the pipe perfectly there will still be gaps.
Why do vent pipes leak.
Now slide the boot down and make sure there is enough caulk to have a seamless circle all the way around.
Find quality vent pipe flashing online or in store.
These gaps should be sealed.
This is why they re installed with a rubber boot.
And begging to caulk around where the boot will go on the roof.