If you have a garage and a backyard, you have two main ways to add a rentable unit: convert the garage or build a new detached ADU. Both are legal, both add value, and both can produce rent. Here's how they compare.
Side-by-side comparison
| Garage conversion | Detached ADU | |
|---|---|---|
| Price range | $110K–$220K for a living unit (studio $110K–$165K; 1-bedroom $150K–$220K) | $230K–$390K (1-bedroom); $390K–$600K+ (2-bedroom or two-story) |
| Typical size | 380–800 sq ft | 600–1,200 sq ft |
| Design and permits | 2–4 months | 3–5 months |
| Construction | 3–5 months | 4–7 months |
| Setbacks | Existing structure usually needs none | 4 ft side and rear |
| Privacy and rent potential | Good | Best |
Plans and city permit fees are separate. If you only want an office or gym with no kitchen, a basic garage conversion costs less ($55K–$95K), but it isn't a rentable unit.
Why a garage conversion costs less
The walls, roof and slab are already there. Most of the money goes into turning the space into a legal home: insulation, windows, a real entry, a kitchen, a bathroom, and bringing plumbing and power to the garage.
Four things move a conversion's price the most:
- Slab condition and height. We core-test the slab, then level it or build a raised subfloor.
- Sewer distance. Plumbing has to be trenched to the main sewer line with the right slope.
- Electrical panel. Many older LA homes have a 100-amp panel that needs to go to 200 amps.
- Ceiling height. Habitable rooms need 7 ft of clear height. Most garages (7'6"–8') are fine.
We recently converted a garage into a full ADU in Van Nuys. See the Garage Conversion ADU – Van Nuys project.
Why a detached ADU can be worth the extra cost
A detached ADU is a new building designed from scratch, so you control the size, layout and look. It gives the tenant or family member the most privacy, which supports higher rent over time. A garage conversion can add a lot of value for its cost, but the detached unit wins on size, privacy and long-term rent.
What about parking?
You keep the driveway, but it's no longer a garage. State law generally waives replacement parking for garage conversions in Los Angeles, especially within half a mile of transit. Rules can change, so we confirm them for your address.
Make sure it's permitted
An unpermitted "bonus room" can't be legally rented and can cause problems when you sell. A real ADU goes through full plan check, Title 24 (California's energy code) compliance, a final inspection and an address assignment. Adding a full kitchen is what makes a converted garage a legal dwelling.
Which one should you choose?
- Choose a garage conversion if you want the lowest cost and fastest timeline, and your garage is in decent shape.
- Choose a detached ADU if you have the yard space and want the most room, privacy and long-term rent.
- Not sure? We visit your property, check the slab, sewer path and electrical panel, and tell you which option makes more sense. The estimate is free.
Common questions
Is a garage conversion cheaper than a detached ADU?
Yes, usually by a wide margin, because the structure already exists. See the price table above.
How long does a garage conversion take in Los Angeles?
About 2–4 months for design and permits, then 3–5 months of construction.
Do I have to replace the garage parking?
In most Los Angeles cases, no. State law generally waives it for garage conversions. We confirm the rules for your address.
