What the South Bay year does to the roof over your head
San Jose roofs rarely die in a storm. They get used up by the sun. The valley lines up long stretches of hot, cloudless days from spring into autumn, and that steady ultraviolet load is what quietly destroys roofing materials here. Asphalt shingles lose the granules that armor them and start to curl. The felt or synthetic underlayment beneath a tile roof bakes until it cracks, even while the tile on top looks brand new. The rubber boots and sealants around vents and pipes stiffen and split. Most of the failing roofs we open in this city were never hit by anything. They were slow-cooked across a decade of valley summers, and the season's first real rain just exposed the damage the sun had already finished.
Then the rain comes, and it comes in a hurry. The wet season here is short and bunched into a few heavy systems, so a roof that limped through summer suddenly has to move a lot of water in a small window. Every dried-out flashing, brittle valley, and clogged low spot gets tested at once. On San Jose's many flat and low-slope homes, water that ought to drain instead pools and probes any aging seam until it wins. That is the entire case for getting eyes on a roof before the rains rather than after, while the weak points can still be sealed in dry weather instead of discovered through the ceiling.