Go on the roof and find the screw or nail. Center the vent pipe over it and, with a wax crayon, trace around the pipe onto the roofing. Drill a pilot hole on the outline with a one-inch spade bit ...

If you have rubber vents which are used for plastic pipe, check to see if they ... If you don’t have any shingles left from the last roofing, be extra careful not to rip any.