You will need only a few materials and they will all be available at your local home improvement store.
Replace rubber boot on metal roof.
Now slide the boot down and make sure there is enough caulk to have a seamless circle all the way around.
Make sure you need a new boot may just need a bit of bitumastic caulk if it is leaking a bit at the duct contact as they commonly do as the rubber gets older.
Step 1 clean pipe and boot.
Replace all rubber boots and replace metal penetration flashing.
And begging to caulk around where the boot will go on the roof.
You do not want to get the sealer between the rubber boot and on the plastic pipe.
Plumbing vent pipes that extend through the roof come with metal flashing or rubber boot type flashing to seal the penetrations.
I put in enough material that it squished out around the entire outside perimeter.
Place the new boot in the hole of the pipe and cut the boot on the line that touches the rim.
Figuring that the rubber collar on the new flashing may split before it s time to strip and replace the roof shingles another 20 years hopefully i first seal the vent pipe to the metal of existing flashing with protectowrap s form flash 2 flashing tape.
Apply a liberal amount of silicone sealer to the old rubber boot.
The slide the boot down the pipe and leave it about 3 above the roof.
Slide the new boot over top and make sure it is sealed completely between the old and new boot.