bove you will see a photo of a recent service call. This is a very common issue that we resolve for our customers. You can see that this pipe collar has a rotted gasket, which over time can happen, and will allow rain water to leak inside the home. In this case, it saturated the attic, and was evident because of a large water mark in an upstairs room.
This type of repair requires a certified professional roofing contractor to handle and ensure a proper water tight seal, and to guarantee the existing shingles and handled carefully and minimize the risk of damage.