Fullerton, Orange County

Room Addition Cost in Fullerton, CA

Fullerton remodeling costs are nearthe California state average. Here's what a typical room addition costs in Fullerton 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 Fullerton

North OC city with charming downtown and historic homes. College town energy drives demand for rental property improvements. More affordable than south OC.

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 Fullerton

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

Culver City
$66,000 – $181,500 | Los Angeles County
Ventura
$60,000 – $165,000 | Ventura County
Sherman Oaks
$63,000 – $173,250 | Los Angeles County
Anaheim
$63,000 – $173,250 | Orange County
Redondo Beach
$66,000 – $181,500 | Los Angeles County
Encino
$66,000 – $181,500 | Los Angeles County
San Diego
$60,000 – $165,000 | San Diego County
Vacaville
$54,000 – $148,500 | Solano County

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