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Garage Conversion Contractors in San Jose, CA

Converting a garage is often the fastest, most affordable way to add a legal living unit in San Jose. The structure, slab, and roof already exist — the work is turning it into conditioned, code-compliant living space with a kitchen and bathroom.

Garage conversion cost in San Jose

Typical range: $110,000–$200,000 all-in, depending on plumbing runs, foundation condition, ceiling height, and finish level.

Editorial estimate — actual costs vary. Full San Jose ADU cost guide.

Permits for garage conversions in San Jose

Garage conversions require building permits even though the structure exists. California law removes the biggest historical obstacle: cities cannot require you to replace the parking you lose. State law caps review of complete applications at 60 days. San Jose's pre-approved ADU program can cut plan review significantly; custom builds commonly take 3–5 months from design to permit.

Contractors serving San Jose

Serves Santa Clara County (San Jose, Campbell, Cupertino, Los Gatos, Sunnyvale) and Alameda County (Oakland, Berkeley, Fremont, Hayward)

Attached ADUs, Detached ADUs, Conversion ADUs, Junior ADUs

Serves Santa Clara, San Mateo, and Alameda counties, including Oakland

Detached ADUs, Garage conversions, Permitting

Serves San Jose, Palo Alto, Menlo Park, Los Gatos, and surrounding Bay Area communities

Detached ADUs, Attached ADUs, Garage conversions, Permitting

Serves Bay Area including Oakland, Berkeley, San Jose, Palo Alto, and Fremont

Garage conversions, Design-build, Permitting

Serves San Jose and Northern California counties including San Francisco, Alameda, Contra Costa, Santa Clara, San Mateo, and Marin

Design-build, Garage conversions, Junior ADUs, Permitting

Serves San Jose, Santa Clara, Sunnyvale, Palo Alto, Los Altos, Saratoga, Mountain View, and other South Bay/Peninsula cities

Design-build, Custom ADUs, Garage conversions, Permitting

Serves Silicon Valley and the Peninsula, including San Jose, Palo Alto, Mountain View, Los Gatos, and Sunnyvale

Design-build, Feasibility studies, Garage conversions, Junior ADUs

Serves San Jose and surrounding South Bay cities including Sunnyvale, Santa Clara, Los Gatos, and Mountain View

Detached ADUs, Garage conversions, Permitting

FAQ

How much does a garage conversion cost in San Jose?

Most garage conversions in San Jose run $110,000–$200,000 depending on plumbing, ceiling height, foundation condition, and finishes. These are editorial estimates — actual quotes vary.

Do I have to replace the parking I lose?

No. California law prohibits cities from requiring replacement parking when a garage is converted to an ADU.

Is my garage suitable for conversion?

Most attached and detached garages can be converted, but a contractor will check the foundation, ceiling height (7'6" minimum in living areas), and utility access. Older garages sometimes need foundation or slab work, which affects cost.

Do garage conversions need permits in San Jose?

Yes — converting a garage into living space always requires permits, even though the building already exists. State law caps review of complete applications at 60 days. San Jose's pre-approved ADU program can cut plan review significantly; custom builds commonly take 3–5 months from design to permit.

How long does a garage conversion take?

Typically 1–3 months of design and permitting plus 2–5 months of construction — noticeably faster than building a detached ADU from scratch.