I have seen small water stains on the ceilings of my home. Just above these stains are 2-inch exhaust pipes from bathrooms. Do these exhaust pipes ever have water in them or can condensation be an issue?

Exhaust pipes? Vents perhaps? They themselves rarely leak but the rubber sealing boots get cracks and the sun degenerates the rubber. I just had to replace one that was leaking in my house. Same problem, water stain on the ceiling.

If the pipe boot is bad you can seal it with roofing cement.

Chuck

Thanks so much for your reply.

A roofer has been out. He replaced the boot and put on a "U" cap to keep any rain water out. He also put tar (roofing cement?) all around the boot. The plumber said the hole in the plywood under the roof shingles where the pipe goes out is unusually big.