ADU design
2-car garage ADU conversion: layouts that fit
By the HyreADU research desk. Last checked .
The short answer
A 2-car garage ADU conversion usually fits a 1-bedroom with a full kitchen and bath, or a large studio.
Put the bathroom and kitchen on the wall nearest the sewer line, the bedroom at the back away from the street, and infill one or both door openings with windows. In California, no new setback or replacement parking can be required.
Layouts that work
- A 1-bedroom: living and kitchen in the front bay, bedroom and bath in the back half.
- A large studio: kitchen on the side wall, sleeping area at the back.
- A studio plus storage: convert one bay and keep a storage area with fire separation.
Measure before you plan
Two-car garages vary in size, so measure the inside clear dimensions and the ceiling height. Check whether the slab steps down and whether the walls have footings. An engineer’s visit is the first spend. The garage conversion vs new build tool lists the tests, and the garage conversion cost calculator adds up the bids.
California rules that help
No setback can be required for an existing structure converted to an ADU in the same location and dimensions (Gov. Code § 66314(d)(7)). The city cannot require replacement parking (§ 66314(d)(11)). If the conversion is 750 square feet or less of interior livable space, no impact fees apply (§ 66311.5).
A mistake to avoid
The mistake to avoid is planning around both door openings as windows without checking the street-facing rules. Some cities set objective standards for windows and entries facing the street. Look them up before the design is fixed. Ideas are on garage conversion ideas.
What to do next: check your lot with the ADU feasibility checker, read the questions to ask an ADU builder, then tell us about your project. Matching is not live yet, so we reply with information, not a quote.
Get ADU optionsQuestions
Can a 2-car garage become a 2-bedroom ADU?
Sometimes, if the floor area allows two bedrooms that meet room minimums and escape rules. Usually it is a 1-bedroom.
Can I add onto the garage during conversion?
Yes, but the added part may need setbacks. Ask your city.
Do I need a new foundation?
Only if the slab and footings cannot carry a home. An engineer decides.
Are plans available?
Most preapproved programs do not cover conversions. See garage conversion plans.
Sources
- Gov. Code § 66314 (ADU standards: parking, setbacks, sprinklers). Checked September 5, 2026.
- Gov. Code § 66311.5 (ADU impact fees, connection fees and capacity charges). Checked September 5, 2026.
- International Residential Code 2021 (R305 ceiling height, R310 emergency escape). Checked September 5, 2026.
- California Energy Commission, 2025 Building Energy Efficiency Standards (Title 24, Part 6). Checked September 5, 2026.
HyreADU is a publisher. It does not design, permit or build ADUs, has no partner builders, and gives no legal, tax, lending or engineering advice.
Rules vary by state and city; California rules are labeled as such. Spotted an error? Tell us through our corrections page. Licensed professionals can also contribute as named sources.