If you own a single-family home in Los Angeles and want to add a rental unit or extra living space, you have two main options: convert your existing garage or build a new detached ADU. Both are legal under California law, but they differ significantly in cost, timeline, and ROI. Here is how to decide.
Garage Conversion: The Quick, Cost-Effective Option
A garage conversion transforms your existing garage structure into a legal living space. Since the shell already exists, you save on foundation and framing costs.
- Cost: $80,000 - $180,000
- Timeline: 2-4 months (permit to completion)
- Permit process: Generally faster since you are working within an existing structure
- Parking: California law exempts garage conversions from parking replacement requirements
- Size: Limited to your existing garage footprint (typically 200-500 sq ft)
- Rental income: $1,200 - $2,200+ per month in LA
Detached ADU: More Space, More Flexibility
A detached ADU is a brand-new standalone structure built in your backyard. More expensive, but offers more design flexibility and typically higher rental income.
- Cost: $150,000 - $350,000+
- Timeline: 4-8 months (permit to completion)
- Permit process: More involved — new foundation, utility connections, and full plan check
- Size: Up to 1,200 sq ft (depending on lot size and zoning)
- Rental income: $1,800 - $3,500+ per month in LA
- Design: Full flexibility — 1-2 bedrooms, custom layout, outdoor space
Side-by-Side Comparison
- Budget under $150k? Garage conversion is your best bet
- Want maximum rental income? Detached ADU generates more
- Need it fast? Garage conversions are 2-4 months vs. 4-8 for detached
- Small lot? Garage conversion uses existing footprint — no additional lot coverage
- Large lot with space? Detached ADU maximizes your property potential
- Want to keep your garage? Build a detached ADU instead
ROI Comparison
Both options deliver strong ROI in Los Angeles. Garage conversions typically have a faster payback period due to lower upfront costs, while detached ADUs generate higher monthly income and add more property value long-term.
A $120k garage conversion renting at $1,800/month pays for itself in about 5.5 years. A $250k detached ADU renting at $3,000/month pays for itself in about 7 years — but adds significantly more to your property value.
Can You Build Both?
Yes. Under California law, many properties can have both a garage conversion ADU and a detached ADU. Some lots also qualify for a Junior ADU (JADU) within the main home. We evaluate your specific lot to determine all available options.
Which Should You Choose?
The right choice depends on your budget, timeline, lot size, and goals. We help you evaluate both options during a free site walkthrough. Learn about garage conversions, explore ADU construction, or request a free estimate.