Quick Answer: Adding a detached garage to a San Jose home costs $60,000-$120,000 for a 1-car garage and $90,000-$180,000 for a 2-car garage (with slab, framing, roofing, drywall, electrical, and a garage door — no plumbing). The process requires a building permit from the City of San Jose, which takes 4-12 weeks to approve. Key zoning checks: the garage must be at least 5 feet from the side and rear property lines in most San Jose R-1 zones, cannot exceed 50% lot coverage combined with the house, and cannot be taller than 14 feet without a variance. A garage can also be designed as a future ADU (with stubbed-in plumbing and minimum ceiling height) to maximize long-term property value.
Garage Addition Cost Guide — San Jose 2025
| Garage Type | Size | Cost Range |
|---|---|---|
| 1-car detached (basic) | 12 × 22 ft (264 sq ft) | $55,000 – $90,000 |
| 1-car detached (with storage/workshop) | 14 × 24 ft (336 sq ft) | $70,000 – $120,000 |
| 2-car detached (standard) | 22 × 24 ft (528 sq ft) | $90,000 – $150,000 |
| 2-car detached (with loft/storage) | 22 × 24 ft + loft | $130,000 – $200,000 |
| 2-car attached (addition to house) | 22 × 24 ft | $100,000 – $185,000 |
| ADU-ready garage (plumbing stubbed in) | 22 × 24 ft | $130,000 – $220,000 |
San Jose Garage Addition Permit Requirements
- Building permit required: All garages over 120 sq ft in San Jose require a building permit. Even a small detached structure over 120 sq ft requires permit and inspection
- Setbacks: In most San Jose R-1 zones, a detached accessory structure (garage) must be at least 4-5 feet from the side and rear property lines. Zero lot line setback is sometimes allowed on one side if both neighbors agree and both properties record the easement
- Lot coverage: Your new garage cannot push total lot coverage (house + garage + all structures) above your zone’s maximum (typically 40-50% for R-1 zones)
- Height limit: Detached accessory structures are typically limited to 14 feet in height or the height of the main house eave, whichever is lower, in San Jose R-1 zones
- Fire separation: If the garage is attached to the house, it must have a fire-rated wall and door (5/8″ Type X drywall, 20-minute rated door with self-closer) between the garage and the living space
Quartz Construction designs and builds garages throughout San Jose, including ADU-ready designs. Get a free garage addition estimate or call (650) 749-7436. CSLB #1003436 | BBB A+.
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