Thousand Oaks, Ventura County

Room Addition Cost in Thousand Oaks, CA

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

Conejo Valley suburb with well-maintained 1960s-80s homes. Family-oriented community with strong renovation ROI. Fire risk from surrounding hills adds defensible space considerations.

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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