Vent pipe opening leak

[Henry in MI]

Don, the vent pipe cutout in the OSB probably isn’t the real problem. Take a trip to your home center or roofing supply store and get a replacement boot that slides over the top of the vent pipe then is roofing nailed under the shingles above the pipe location. There are some variations of these but most are made to be cut for different size pipe and to allow for variations in roof pitch. Since the bottom of the boot is sealed by the shingles, it’s only the top of the boot that has to be sealed with caulk. The roof will actually move up and down with changes in temperature, humidity and air pressures so be sure that you get a good seal from the top of the boot to the pipe. Leaks there are common until the original ones are replaced with upgraded ones. That’s something else that contractors may tend to skimp on since they are rarely seen or noticed. Be careful on your roof.

Henry in MI