Vent Flashing Failure
Your plumbing system includes “vent” pipes that pass through the roof. And like any other roof penetration, that sometimes means trouble. There are two kinds of flashing used to seal vents: a “boot” that relies on a snug rubber seal, and all-metal flashing with soft lead that can be bent over and into the pipe. Some versions are made completely from lead; others are galvanized steel with a lead collar. When any type of vent flashing fails, the solution is to replace it. To see how, read more on plumbing vent flashing.
When a large hailstone hits an asphalt shingle, it can tear or even puncture the shingle. But usually, it just knocks granules off the surface. When a shingle loses its protective layer of granules, UV rays from the sun begin to destroy it. More granules fall off around the damaged spot and the bruise grows. The damage may not be obvious at first, so if you suspect hail damage, get an inspection from a roofing contractor. Most offer free hail damage inspections.