Mission Viejo, Orange County

Room Addition Cost in Mission Viejo, CA

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

Budget
$63,000
$210/sqf
Mid-Range
$110,250
$368/sqf
High-End
$173,250
$578/sqf

Cost breakdown

Foundation & Framing
30%$33,075
Roofing & Exterior
15%$16,538
Mechanical (HVAC, Electrical)
15%$16,538
Interior Finishes
20%$22,050
Windows & Doors
10%$11,025
Permits & Engineering
10%$11,025

Breakdown based on mid-range estimate of $110,250

Typical Timeline
3-6 months
Permits Required

Building permit, structural engineering, possibly zoning approval.

Remodeling in Mission Viejo

Master-planned community with well-maintained homes from the 1970s-90s. Many are now due for kitchen and bathroom updates. HOA restrictions may limit exterior changes.

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 Mission Viejo

Kitchen Remodel
$31,500 – $94,500
Bathroom Remodel
$15,750 – $50,400
ADU / Guest House
$131,250 – $315,000
Roof Replacement
$13,125 – $39,375
Exterior Paint
$5,250 – $18,375
Whole House Remodel
$283,500 – $945,000

Room Addition cost in other California cities

Oakland
$72,000 – $198,000 | Alameda County
Bakersfield
$48,000 – $132,000 | Kern County
Los Gatos
$78,000 – $214,500 | Santa Clara County
Berkeley
$75,000 – $206,250 | Alameda County
Saratoga
$81,000 – $222,750 | Santa Clara County
Atherton
$84,000 – $231,000 | San Mateo County
Pacifica
$72,000 – $198,000 | San Mateo County
San Anselmo
$72,000 – $198,000 | Marin County

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