Which San Francisco roof do you have?
Most city homes have one of three: a flat or low-slope roof behind a parapet (common in the Sunset, Richmond and Excelsior), a steep Victorian or Edwardian roof in older central neighborhoods, or a mix of both. Each ages differently.
| Roofing material | Estimated life (years) |
|---|---|
| Asphalt shingles (3-tab) | 20 |
| Asphalt shingles (architectural) | 30 |
| Wood shakes or shingles | 25 |
| Metal | 40 to 80 |
| Clay or concrete tile | 100+ |
| Slate | 60 to 150 |
| Built-up roofing (flat) | 30 |
| Modified bitumen (flat) | 20 |
| TPO (flat) | 7 to 20 |
| EPDM rubber (flat) | 15 to 25 |
Source: InterNACHI's estimated life expectancy chart.
How does San Francisco weather change those numbers?
San Francisco sits entirely in climate zone 3. It rarely gets the summer heat that shortens shingle life inland. What wears roofs here is moisture: fog that keeps surfaces damp, salt that corrodes metal flashing near Ocean Beach, and winter rain that finds every gap at a parapet or scupper.
How can I find out when my roof went on?
Search your address in DataSF's building permit dataset. Reroof permits are flagged, and the record is close to complete from 1993 on. No permit doesn't always mean an old roof, but it's a starting point.
What shortens a flat roof's life most?
Standing water. Drains clogged with leaves, a sagging deck or a missing cricket behind a chimney keep water on the membrane, and seams fail first where water sits.
Every roofer we work with is licensed, insured and highly reviewed by Bay Area homeowners.
Get a free replacement quoteFrequently asked questions
Is a 20-year-old flat roof in the Sunset due for replacement?
It may be. InterNACHI lists modified bitumen at about 20 years. Have a roofer check seams, drains and the parapet.
Does fog shorten roof life?
It keeps roofs damp, which encourages moss and corrosion, especially on flashing and fasteners near the ocean.
How do I find my last reroof permit?
Search your address in DataSF's building permit dataset; reroof permits are flagged.
Sources
Sources reviewed November 11, 2026. Figures are published estimates and official fees, not quotes. Confirm prices, permits and requirements with your contractor and building department. This page is general information, not legal or insurance advice.