Garage Conversion vs. New Construction ADU
Which ADU type is right for your property? Compare costs, timelines, rental income, and ROI to make the right decision.
Side-by-Side Comparison
| Feature | Garage Conversion | New Construction ADU |
|---|---|---|
| Construction Estimate | Property-specific written estimate | Property-specific written estimate |
| Timeline | 4–6 months | 6–12 months |
| Max Size | 400–600 sq ft (limited by garage) | Up to 1,200 sq ft |
| Rental Income | $1,500–$2,200/mo | $2,000–$3,500/mo |
| Property Value Increase | $100,000–$180,000 | $150,000–$350,000 |
| Foundation Work | Minimal (existing slab) | New foundation required |
| Design Flexibility | Limited by existing structure | Full creative freedom |
| Backyard Impact | None | Reduces backyard space |
Which Is Right for You?
Choose a garage conversion if: you want to reuse an existing detached garage, minimize new structural work, preserve backyard space, or start generating income sooner.
Choose new construction if: you want the largest possible unit, maximum rental income, full design control, or you don't have an existing garage to convert.
Do both: California law allows one converted ADU plus one new construction ADU on the same property — many homeowners convert first, then build later.
Not sure which option fits your property?
Our team will evaluate your property and recommend the best approach — free.
Book Free Consultation (866) 668-4264