Plumbing vent boots
Plumbing vent boots can be all plastic, plastic and metal, or even two-piece metal units. Check plastic bases for cracks and metal bases for broken seams. Then examine the rubber boot surrounding the pipe. That can be rotted away or torn, allowing water to work its way into the house along the pipe. With any of these problems, you should buy a new vent boot to replace the old one.
However, if the nails at the base are missing or pulled free and the boot is in good shape, replace them with the rubber-washered screws used for metal roofing systems. You’ll find them at any home center with the rest of the screws. You’ll have to work neighboring shingles free on both sides. If you don’t have extra shingles, be careful when you remove shingles so they can be reused. Use a flat bar to separate the sealant between the layers. Then you’ll be able to drive the flat bar under the nail heads to pop out the nails.
Rubberwashered screw SOLUTION: Replace the old boot. Screw the base to the roof with rubber-washered screws. Don’t use nails. They’ll just work loose over time.
Nail holes PROBLEM: When the source of a leak is gasket-type vent flashing, the culprit is usually a cracked gasket or missing or loose nails. Rotted gasket