How to Install a Plumbing Vent Through a Metal Roof
- 1). Apply a bead of caulk to the bottom of the pipe boot. Slide the pipe boot over the top of the plumbing vent. Push the boot to the bottom of the vent so that it rests on the roof. Press on the metal ring around the base of the boot to bend the ring to fit the contour of the roof.
- 2). Drive a self-tapping screw through each of the holes in the retaining ring of the pipe boot with your drill. Tighten the screws while being careful not to strip them by using too much torque on the small fasteners.
- 3). Apply a bead of caulk around the seam between the bottom of the boot and the roof. Apply a bead of caulk around the seam between the top of the boot and the vent pipe to complete the seal and protect your home from water damage.
Source...