Bay Area ADUs and remodels,
built on schedule.

A detached ADU in the Bay Area typically runs $250,000–$450,000 turnkey depending on size, site access and utility runs; a garage conversion is far cheaper, usually $120,000–$200,000 because the shell and the slab already exist. We give a written range after a free site walk.

Yes — both need a building permit, and California state law now forces cities to approve code-compliant ADUs within 60 days. We prepare the drawings, file with your city, carry them through plan check and close the permit after final inspection.

Plan on 3–5 months for design, engineering and plan check, then 4–7 months on site. Garage conversions run 8–14 weeks of construction. City plan-check queues are the part that varies most, which is why our city pages list local timelines.

The San Francisco Bay Area and Greater Sacramento — San Jose, Oakland, San Francisco, Fremont, Berkeley, Palo Alto, Sunnyvale, Santa Clara, Mountain View, Redwood City, San Mateo, Walnut Creek, Concord, Pleasanton, Livermore and Sacramento — and roughly 300 miles around the Bay. Each city has its own page with local pricing and permit notes.

Yes. Zen Construction is a licensed California general contractor, CSLB #1041370, bonded and insured. Verify it yourself at cslb.ca.gov under Check a License — we would tell you to do that with any contractor.

Yes, in seconds and for free. Upload a photo of the room or the yard to our AI design preview and it renders the remodel in the style you pick — the fastest way to agree on a direction before anyone pays for drawings.