The fastest, most affordable path to an ADU
Your garage already has a foundation, a roof, and walls — the three most expensive parts of any new build. Converting it into a permitted living space costs $95,000–$160,000 for 400–650 sq ft, against $185,000+ for a new detached cottage, and the construction phase runs 3–5 months instead of 6–8. Because the structure exists, permit review is shorter too.
What a garage conversion actually involves
It starts with a structural assessment of the existing garage: can the slab, framing, and roof carry a dwelling, and what reinforcement is needed. From there the scope is conversion, not construction — insulation and weatherproofing to bring the shell to residential code, full plumbing, electrical and HVAC, egress-compliant windows and a proper entry door, and interior finishes. We run the permits start to finish and hand over a certificate of occupancy.
Detached or attached garage — it matters for permits
A detached garage becomes a detached ADU; a garage attached to the house becomes an attached ADU. The classification changes which code standards apply and how utilities are metered, not whether the project is possible — under HB 1337 a single-family lot has the right to two ADUs either way. Weighing a conversion against building new? Our guide garage conversion vs. DADU walks through the trade-offs.