Why Roofs Leak in San Antonio: Local Climate Factors
Roofs in San Antonio and South-Central Texas face distinct weather stresses that differ significantly from other parts of the country:
1. Extreme Summer Heat & Thermal Expansion
Attic and roof surface temperatures in San Antonio frequently exceed 150°F during long summer heatwaves. This thermal cycling causes metal step flashings, valley pans, and shingle asphalt to expand and contract repeatedly, breaking caulk lines and pulling fasteners loose.
2. Hail Micro-Fractures
Spring hailstorms across Bexar County bruise asphalt shingle mats without immediately puncturing through. As sunlight bakes the unprotected fiberglass mat, the material shrinks and cracks, allowing sudden water entry during the next severe convective downpour.
3. Wind-Driven Rain Through Vents
Severe thunderstorm squalls push torrential rain horizontally. Inadequately baffled ridge vents, off-ridge box vents, and unsealed siding-to-roof intersections frequently allow water to bypass traditional gravitational shedding.
4. Degraded Pipe Boots & Skylight Seals
High UV levels degrade synthetic neoprene plumbing pipe collars in 5 to 8 years, leaving open gaps around plumbing vents directly over interior bathrooms and kitchens.