Not all roof leaks are caused by a deteriorated waterproofing materials. Many other building components can leak. Vulnerable HVAC equipment, masonry walls, plumbing fixtures, condensation lines, skylight frames and metal fascia systems are often misdiagnosed as roof leaks. The mystery is compounded by the fact that many leaks only show up in severe weather conditions (violent thunderstorms or freezing rain). Also, roof leaks can "travel" from the actual penetration point 40 or 50 feet before falling to the building interior. These many variables make leak investigation and repair a tricky process.