Another problem that occurs with roofs put on in the last 10 years is the deterioration of a plumbing stack boot that is made of neoprene. It has a tendency to dry out and crack allowing water to run down the pipe into your home through the walls. Sometime the ony evidence of a leak occurs in the basement or whereever the first bend in the pipe is located. Installing a new boot will last the remaining life of th eroof. If you are in need of a new roof, I would recommend a lead plumbing stack cover which will outlast any roof system.