Side-by-side comparison
Garage conversion vs Detached ADU build
Both add an independent living unit to the lot. Garage conversion reuses an existing structure; detached ADU builds from scratch. The trade-offs span cost, parking impact, and the unit's character.
Option A
Garage conversion
Reuse existing garage shell
Option B
Detached ADU build
New structure from foundation
Dimension by dimension
How they stack up.
| Dimension | Garage conversion | Detached ADU build |
|---|---|---|
| Cost (typical) | $80,000–$180,000 | $180,000–$400,000 |
| Parking impact | Loses garage parking | No parking loss |
| Construction time | 10–16 weeks | 20–28 weeks |
| Unit independence | Connected to main house | Fully separate |
| Permit complexity | Conversion permit + ADU classification | Full ADU permit + structural |
| Rental income suitability | Acceptable for long-term tenants | Premium for short-term/long-term |
Pick Garage conversion
Garage conversion is the right call when budget is the primary constraint, when the existing garage isn't actively used for parking, and when the homeowner can accept the connected-to-main-house feel.
Pick Detached ADU build
Detached ADU is the right call when parking matters, when privacy and unit independence are priorities, and when the lot supports a separate footprint with appropriate setbacks.
Sources
- Florida ADU rules update 2026
- Clay/Duval/St. Johns County conversion permitting
Talk it through with Mark
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