Vent pipes are roof penetrations so holes are created.
How to seal reaeal pipe boot on roof.
Place the new boot in the hole of the pipe and cut the boot on the line that touches the rim.
Now slide the boot down and make sure there is enough caulk to have a seamless circle all the way around.
Roof water damage repair small hole in roof leaking metal roof how to stop.
Why do vent pipes leak.
The flashing of the vent pipes.
How to seal a plumbing vent pipe on the roof.
And begging to caulk around where the boot will go on the roof.
These gaps should be sealed.
Plumbing vent pipes on house roofs are covered with a metal square of flashing and sealed with silicone caulking.
The slide the boot down the pipe and leave it about 3 above the roof.
This is why they re installed with a rubber boot.
Even if the hole matches the size of the pipe perfectly there will still be gaps.
As mentioned there s a rubber boot that serves as a seal to prevent water from leaking in.