Alameda, Alameda County

Room Addition Cost in Alameda, CA

Alameda remodeling costs are 15% abovethe California state average. Here's what a typical room addition costs in Alameda in 2026, based on a 300 sqf project.

Budget
$69,000
$230/sqf
Mid-Range
$120,750
$402/sqf
High-End
$189,750
$633/sqf

Cost breakdown

Foundation & Framing
30%$36,225
Roofing & Exterior
15%$18,113
Mechanical (HVAC, Electrical)
15%$18,113
Interior Finishes
20%$24,150
Windows & Doors
10%$12,075
Permits & Engineering
10%$12,075

Breakdown based on mid-range estimate of $120,750

Typical Timeline
3-6 months
Permits Required

Building permit, structural engineering, possibly zoning approval.

Remodeling in Alameda

Island city with charming Victorian and Craftsman homes. Limited contractor access (two entry points) can affect scheduling. Historic preservation requirements in certain districts add design constraints.

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 Alameda

Kitchen Remodel
$34,500 – $103,500
Bathroom Remodel
$17,250 – $55,200
ADU / Guest House
$143,750 – $345,000
Roof Replacement
$14,375 – $43,125
Exterior Paint
$5,750 – $20,125
Whole House Remodel
$310,500 – $1,035,000

Room Addition cost in other California cities

Visalia
$45,000 – $123,750 | Tulare County
Dublin
$66,000 – $181,500 | Alameda County
Pleasanton
$69,000 – $189,750 | Alameda County
Concord
$60,000 – $165,000 | Contra Costa County
Vallejo
$57,000 – $156,750 | Solano County
Pittsburg
$57,000 – $156,750 | Contra Costa County
South San Francisco
$72,000 – $198,000 | San Mateo County
Belmont
$75,000 – $206,250 | San Mateo County

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