Martinez, Contra Costa County

Room Addition Cost in Martinez, CA

Martinez remodeling costs are nearthe California state average. Here's what a typical room addition costs in Martinez in 2026, based on a 300 sqf project.

Budget
$60,000
$200/sqf
Mid-Range
$105,000
$350/sqf
High-End
$165,000
$550/sqf

Cost breakdown

Foundation & Framing
30%$31,500
Roofing & Exterior
15%$15,750
Mechanical (HVAC, Electrical)
15%$15,750
Interior Finishes
20%$21,000
Windows & Doors
10%$10,500
Permits & Engineering
10%$10,500

Breakdown based on mid-range estimate of $105,000

Typical Timeline
3-6 months
Permits Required

Building permit, structural engineering, possibly zoning approval.

Remodeling in Martinez

County seat with a mix of Victorian and mid-century homes. More affordable than southern Contra Costa. Waterfront area has specific building requirements.

A room addition adds square footage and value to your home. Costs depend on whether it's a simple bump-out, a second story, or a full wing addition with plumbing.

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Other projects in Martinez

Kitchen Remodel
$30,000 – $90,000
Bathroom Remodel
$15,000 – $48,000
ADU / Guest House
$125,000 – $300,000
Roof Replacement
$12,500 – $37,500
Exterior Paint
$5,000 – $17,500
Whole House Remodel
$270,000 – $900,000

Room Addition cost in other California cities

Millbrae
$72,000 – $198,000 | San Mateo County
Bakersfield
$48,000 – $132,000 | Kern County
Santa Monica
$72,000 – $198,000 | Los Angeles County
Mission Viejo
$63,000 – $173,250 | Orange County
San Clemente
$66,000 – $181,500 | Orange County
Los Altos
$81,000 – $222,750 | Santa Clara County
Glendale
$63,000 – $173,250 | Los Angeles County
South San Francisco
$72,000 – $198,000 | San Mateo County

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