Bitumen roofs are very delicate. Goooood question.:thumbup: These roofs are notorious for off-gasing during hot weather. This causes heavy expansion and shrinkage. The simple solution is to contact your local roofing supply specialist and purchase anti-off gasing spray. This can be applied by any do-it-yourselfer with a simple garden weed sprayer. The cost savings is ASTRONOMICAL compared to what a contractor will charge.Having an issue with water leaking in around a water supply pipe that comes up through the roof. Any advice on the appropriate sealant to use to repair would be appreciated.