How does the estimator work?
The math is geometry, not pricing. Footprint is living area divided by stories, plus an attached garage under the same roof. A pitch factor converts footprint to sloped surface: a 6-in-12 roof has about 12% more surface than a flat one, a 12-in-12 roof about 41% more. We then add 5% to 20% for overhangs. Divide by 100 and you have roofing squares.
What do typical San Francisco homes come to?
These examples use the same geometry. They describe roof area only, not price.
| Example home | Footprint under the roof | Pitch | Roofing squares (approx.) |
|---|---|---|---|
| Two-story Sunset or Parkside row house, 1,600 sq ft | about 800 sq ft | flat or nearly flat | 8 to 10 |
| Victorian with a pitched front and flat rear, 2,400 sq ft on three levels | about 800 sq ft | 8-in-12 pitch | 10 to 12 |
| Westwood Park bungalow, 1,400 sq ft, one story | about 1,400 sq ft | 6-in-12 pitch | 16 to 19 |
What makes a roof in San Francisco cost more than its size suggests?
San Francisco square footage is a weak guide on its own. Many Sunset and Richmond houses have a nearly flat roof hidden behind a parapet, so the job is a membrane system with drains and parapet flashing rather than shingles. Victorians and Edwardians mix steep front gables with flat rear sections, which means two crews' worth of skills on one roof. Row houses with shared walls and no side yard push everything through the house or up a hoist, and the dumpster needs street space through the reroofing permit.
What price range should I expect?
National cost surveys such as the Cost vs. Value report put a full asphalt-shingle reroof in the tens of thousands of dollars, with metal well above that. We don't publish a per-square or per-city price, because layers, decking, access and material swing real bids too much for one number to be honest. For your actual price, request a free written estimate: a licensed roofer measures the roof and prices your exact scope.
What should I have ready for an estimate?
- Living area and stories (from a listing or tax record)
- Known leaks and where they show inside
- Solar panels, skylights or a chimney
- Access notes: stairs, gates, shared walls
Related: what drives roof replacement cost, metal roofs, dry rot and decking, solar removal and reinstall and our quote checker.
Every roofer we work with is licensed, insured and highly reviewed by Bay Area homeowners.
Get a free replacement quoteFrequently asked questions
How do I convert my house size to roofing squares?
Divide living area by stories, add a garage under the same roof, multiply by a pitch factor such as 1.12 for a 6-in-12 roof, add 5% to 20% for overhangs, then divide by 100.
Can I get a price per square foot from you?
We don't publish one. Real bids vary with layers, decking, material and access, so ask for a free written estimate that shows the scope.
Why does my small San Francisco house have a big roof bid?
Flat sections behind parapets, three-story access and street-space logistics add labor that square footage doesn't show.
Sources
- Cost vs. Value 2025 report (JLC / Zonda)
- SF.gov: apply for a reroofing permit
- DataSF: building permits
- CSLB: check a license
Sources reviewed November 12, 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.