Why roofs fail
Heat above and humidity below, working on the same roof from both sides for most of the year.
- 1 Ridge caps. Full sun, no shade, ever. They cook before anything else on the roof does.
- 2 The field. Shingle, or tile sitting on felt that is doing the actual waterproofing.
- 3 Valleys. Two slopes emptying through one line, every single afternoon.
- 4 Flashing. The metal salt air finds long before it touches the covering.
- 5 The vent boot. Rubber baked brittle by sun, and the bay area’s most ordinary leak.
- 6 Eaves. Where the Florida room ties in, and where the hardware corrodes first.
The six
Why the Bay is hard on a roof
Ultraviolet exposure that never takes a season off. Tile underlayment that fails twenty years before the tile does. Salt eating the flashings on every street near the water. Valleys holding debris through four months of afternoon rain. Florida rooms roofed in shingle when they needed a membrane. And attics that trap heat above and condense moisture below. The field is rarely the problem; the edges of it always are.