Budget planning guide

Room Addition cost in San Jose, CA

A transparent starter-scope range for homeowners planning room addition in San Jose, CA. Review the assumptions, then use the project estimator for your own scope.

Starter-scope range

$13,590–$19,190

Planning midpoint: $15,990

The planning model applies a higher regional cost factor for this market.

What the model includes

Starter scope and assumptions

Adjust quantities for your project

Foundation

200 sq ft × $22.5

$4,500

Framing

200 sq ft × $18

$3,600

Roofing

220 sq ft × $12

$2,640

Electrical & Plumbing

1 lump sum × $5,250

$5,250

This is a budgeting example based on a defined starter scope, not a quote or a live survey of local bids. Actual pricing depends on measurements, site conditions, material choices, permits, contractor availability, and the final scope.

Local guides

Compare starter scopes by city

New York, NYLos Angeles, CAChicago, ILHouston, TXPhoenix, AZPhiladelphia, PASan Antonio, TXSan Diego, CA

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