Why a planned-community roof in Cerritos ages on a schedule
Most neighborhoods grow up in fits and starts, a house here, a remodel there, over generations. Cerritos and its neighbors did not. They were laid out and constructed as coordinated developments, so the houses on a given street are close cousins in age and in build. For a roofer that is unusually useful information. It means the roof that just failed on one home is a strong preview of what the identical roof three doors down is about to do. We see the same vintage of shingle reaching the same exhaustion point across a whole tract within a season or two of each other, and we plan and price accordingly.
The inland heat is the engine that drives the schedule. We are far enough from the coast that the morning marine layer usually burns off before lunch, and from late spring deep into autumn the roofs out here bake under a sun that never seems to let up. Asphalt is a petroleum product, and that relentless heat steadily drives the volatile oils out of it. Once those oils are gone the shingle goes stiff and brittle, the surface granules begin to shed into the gutters, and the mat underneath starts to curl and split. None of that leaks while the weather stays dry. It waits.