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How big is my roof, and what does that mean for new roof cost in the Bay Area?

Short answerExpect a full replacement to run in the tens of thousands of dollars for most homes in the Bay Area, with size, pitch and local factors deciding where yours falls. This page turns your home's size into an approximate roof area in squares, lists the cost factors to check, and connects you with a roofer for an exact price.

Every roofer we work with is licensed, insured and highly reviewed by Bay Area homeowners.

Updated · Sources reviewed November 12, 2026 · By Bay Area Roof Replacements

  • Active C-39 roofing license, checked on CSLB
  • Contractor's bond and workers' comp on file
  • Tear-off, permit and warranty paperwork handled
  • Free written estimate, no obligation

How does the estimator work?

A roofing square is 100 square feet. To estimate yours, take the area each floor covers (living area divided by stories), add a garage if it shares the roof, and scale up for slope, because pitched surfaces are longer than the floor below them. Eaves and overhangs add roughly another 5% to 20%. The roofer's measurement replaces all of this.

Roof size and cost-factor estimator

Which of these apply? (each one tends to push the price up)

What do typical the Bay Area 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.)
Single-story tract home, 1,500 sq ft about 1,900 sq ft 4-in-12 pitch 21 to 24
Two-story home, 2,200 sq ft about 1,500 sq ft 6-in-12 pitch 18 to 20
Flat-roof row house or Eichler, 1,600 sq ft about 1,600 sq ft flat or nearly flat 17 to 19
Steep hillside home, 2,500 sq ft about 1,250 sq ft 10-in-12 pitch 17 to 20

What makes a roof in the Bay Area cost more than its size suggests?

The nine counties hold every roof type there is: flat roofs behind parapets in San Francisco, Eichlers in the South Bay and Marin, tile in many newer subdivisions, shake in wine country and steep hillside roofs from Mill Valley to the Oakland hills. Rules differ too: inland and South Bay climate zones require cool-roof products on qualifying reroofs, and fire hazard zones require Class A assemblies. Our regional guides cover each area's details.

What price range should I expect?

Most full replacements are five-figure projects. The Cost vs. Value report supports that broad frame for asphalt shingles, with metal costing substantially more, but it can't price your roof. Treat squares as a way to compare bids, not to predict them. 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 quote

Frequently asked questions

What is a roofing square?

100 square feet of roof surface. Roofers measure and price in squares; the number depends on footprint and pitch, not just living area.

Is the estimator's result a quote?

No. It estimates roof area and lists cost factors. A licensed roofer measures the roof and prices your exact scope.

Which Bay Area region is cheapest for a new roof?

No reliable published comparison exists. Roof type, size, layers and access matter far more than the county, so compare written estimates.

Related questions

Sources

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.