Quick Answer: Quartz Construction converts garages to livable ADU space in San Ramon, CA. A standard 2-car garage conversion (400-500 sq ft) to a full ADU costs $76,500-$177,000 in San Ramon — including new insulation, drywall, windows (replacing the garage door opening), HVAC (mini-split), full kitchen, bathroom, flooring, electrical upgrade, and permit fees. A garage converted to a non-dwelling bonus room or office costs $30,000-$72,000. California state law (AB 68) requires San Ramon to allow garage conversions to ADUs without requiring replacement parking, making garage conversions one of the most accessible ADU types for Bay Area homeowners. CSLB #1003436. Call (650) 749-7436 for a free San Ramon garage conversion estimate.
Garage Conversion Types in San Ramon
Helpful Resources:
- Garage to ADU (full dwelling) — add kitchen, bathroom, HVAC, and separate entrance; legally rented for income
- Garage to JADU (Junior ADU) — up to 500 sq ft, shares bathroom with main house, requires owner-occupancy
- Garage to home office — insulation, drywall, electrical, AC, flooring; no kitchen or full bathroom required
- Garage to bonus room / family room — open to main house or connected via interior door
- Garage to bedroom suite — closet, bathroom, separate entrance for in-law or caregiver
Garage Conversion Cost in San Ramon 2025
| Conversion Type | Size | Cost Range |
|---|---|---|
| Garage to ADU (full kitchen + bath) | 400 – 600 sq ft | $76,500 – $177,000 |
| Garage to JADU (no separate kitchen) | Under 500 sq ft | $45,000 – $95,000 |
| Garage to home office | 200 – 400 sq ft | $18,000 – $40,000 |
| Garage to bonus room | 400 – 600 sq ft | $25,000 – $60,000 |
| Garage to bedroom suite (with bath) | 300 – 500 sq ft | $45,000 – $95,000 |
Garage Conversion ADU Permit Requirements in San Ramon
- Building permit required for all garage conversions (change of use from garage to living space)
- Electrical permit required for upgraded circuits (240V, 20A kitchen circuit, GFCI)
- Plumbing permit required for kitchen and bathroom rough-in through concrete slab
- Mechanical permit required for HVAC (mini-split) installation
- San Ramon cannot require replacement parking — state ADU law (AB 68/AB 881) prohibits this
- Title 24 energy compliance: R-15 wall insulation, R-38 ceiling, dual-pane windows
Garage Conversion Rental Income Potential in San Ramon
A garage conversion ADU in San Ramon rents for $2,000-$3,500/month in 2025 depending on size and proximity to employers (BART, tech campuses). A 1-bedroom garage ADU at $2,400/month generates $28,800/year in rental income. At a total construction cost of $100,000-$130,000, the gross payback period is 3.5-5 years before accounting for property value increase (typically $150,000-$250,000 added value to a San Ramon property with a permitted ADU). Call us to discuss your San Ramon garage conversion ROI.
Serving San Ramon (94583) and all Bay Area communities. ADU construction services | Room additions | CSLB #1003436 | (650) 749-7436
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What Our Bay Area Clients Say
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"Quartz Construction did an amazing job on our kitchen remodel. The team was professional, on time, and the results exceeded our expectations. Highly recommend to any Bay Area homeowner!"
— Michael T. |
"We hired them for a bathroom remodel in our San Jose home. From permitting to final walkthrough, everything was handled perfectly. The tile work is stunning. 5 stars without hesitation."
— Sarah L. |
"Just finished our ADU garage conversion. The project came in on budget and on schedule — rare in the Bay Area! The rental income already started. Could not be happier with Quartz Construction."
— David R. |
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Quartz Construction & Remodeling | CSLB #1003436 | Licensed, Bonded & Insured
Phone: (650) 749-7436
Address: 1777 Hamilton Ave #1080, San Jose, CA 95125
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