San Jose / Bay Area ADU Builders
Bay Area ADUs command premium prices — but also premium rents. The region is home to local design-build firms offering multi-year warranties, plus the prefab manufacturers in Redwood City and San Francisco shipping factory-built ADUs statewide.
5 builders based in the San Jose / Bay Area area
Cost basics
Detached ADU projects commonly run $150,000–$400,000+ depending on size and finishes; garage conversions cost less. Builders focused on the San Jose / Bay Area area can give project-specific pricing — several publish real example budgets on their profiles.
Permit basics
State law requires by-right approval of compliant ADUs in most cases, but local rules (setbacks, height, parking, historic districts) vary. Confirm requirements with your city's planning department before finalizing a design — or ask a local design-build firm, which handles permitting as part of the project.