How the Anaheim climate quietly ages a roof
The Southern California sun is the slowest and most patient enemy a roof here has. Day after day of intense ultraviolet light dries out asphalt shingles, makes them brittle, and breaks down the sealant strips that hold them flat. On a tile roof the tiles themselves shrug off the sun, but the underlayment beneath them, the layer that actually keeps water out, cooks in the trapped attic heat and grows brittle long before the tiles ever look worn. This is the trap a lot of Anaheim homeowners fall into. The roof looks perfectly healthy from the curb while the part that matters has quietly reached the end of its life underneath.
Then there is the wind. When a Santa Ana event sets up, dry desert air pours through the passes and down the canyons into the Anaheim basin at highway speed, and it arrives in gusts rather than a steady push. That is the worst case for a roof. Gusting wind gets under the edge of a lifted shingle or a loose tile and works it loose a little more with each pass, and once one piece goes the wind has a new edge to grab. A roof that has been baking and drying all summer is brittle and poorly sealed exactly when the fall and winter wind season arrives, which is why so many Anaheim roof failures show up right after the first big blow rather than during the rare heavy rain.