The slow grind that ages a roof in north Orange the area
If you want to know what is going to wear out your Placentia roof, do not look for a single bad storm. Look at the calendar. The thing that ages a roof here is the accumulation of ordinary days, and the heaviest hand in that accumulation is the sun. We sit well inland of the coastal marine layer, so our summers run hot and the ultraviolet load is heavy and persistent. On an asphalt shingle roof that radiation dries the asphalt out and drives off the protective granules until the mat underneath is exposed. On a tile roof the tile barely notices the sun, but the felt underlayment hidden beneath it bakes in the trapped attic heat, surrenders its oils, and turns stiff and brittle. Because that underlayment is the layer actually keeping water out of a tile roof, its quiet decline is the single most frequent reason an older Placentia tile roof starts to leak while every tile up top still looks flawless.
The wind is the second force, and in Placentia it has a particular character. When the Santa Anas kick up in autumn they pour down out of the high desert through the Chino Hills and the canyon gaps to the northeast, and the north and eastern edges of town catch them early and hard. Wind almost never shreds a roof that is in good shape, but it is ruthless about exposing one that is already compromised. It peels back shingles whose seal has dried out, it pries beneath tiles that have lost a fastener or slipped a course, and it carries dust and dropped branches across the slopes. Then, after a long parched autumn, the winter rain arrives in a concentrated burst and pours straight onto a roof full of the small openings the heat and wind spent all year creating. That one-two pattern, long punishment followed by a sudden soaking, is the cycle a Placentia roof has to outlast, and it is the cycle we build every job to survive.