Redwood City, San Mateo County

ADU / Guest House Cost in Redwood City, CA

Redwood City remodeling costs are 25% abovethe California state average. Here's what a typical adu / guest house costs in Redwood City in 2026, based on a 500 sqf project.

Budget
$156,250
$313/sqf
Mid-Range
$250,000
$500/sqf
High-End
$375,000
$750/sqf

Cost breakdown

Foundation & Framing
25%$62,500
Mechanical (HVAC, Plumbing, Electrical)
20%$50,000
Interior Finishes
20%$50,000
Exterior & Roofing
15%$37,500
Kitchen & Bath Fixtures
10%$25,000
Permits, Plans & Engineering
10%$25,000

Breakdown based on mid-range estimate of $250,000

Typical Timeline
4-8 months
Permits Required

Building, electrical, plumbing, mechanical. May require plan check.

Remodeling in Redwood City

Downtown Redwood City's revitalization has sparked residential renovation in surrounding neighborhoods. Mix of older cottages and mid-century homes. The city is relatively contractor-friendly on permitting.

California allows ADUs on most residential lots since 2020. An ADU adds living space and rental income. Cities must approve or deny within 60 days of a complete application.

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Other projects in Redwood City

Kitchen Remodel
$37,500 – $112,500
Bathroom Remodel
$18,750 – $60,000
Room Addition
$75,000 – $206,250
Roof Replacement
$15,625 – $46,875
Exterior Paint
$6,250 – $21,875
Whole House Remodel
$337,500 – $1,125,000

ADU / Guest House cost in other California cities

San Clemente
$137,500 – $330,000 | Orange County
Sausalito
$162,500 – $390,000 | Marin County
Hillsborough
$175,000 – $420,000 | San Mateo County
Half Moon Bay
$150,000 – $360,000 | San Mateo County
Fremont
$143,750 – $345,000 | Alameda County
San Bruno
$150,000 – $360,000 | San Mateo County
Millbrae
$150,000 – $360,000 | San Mateo County
San Jose
$156,250 – $375,000 | Santa Clara County

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