A garage conversion turns an existing garage into a dwelling. In the City of Atlanta, a converted detached garage is a detached ADU, so it has to be in a district that allows one and stay within the size and height limits. An attached garage is a different story, because the city does not currently allow attached ADUs.
Can I convert my garage in the City of Atlanta?
It depends on the garage and the district. A detached garage on an R-4, R-4A or R-5 lot can be a candidate, as of October 2026, subject to the 750 sq ft and 20-foot limits City Planning lists for detached ADUs. A garage built into or attached to the house would create an attached ADU, which City Planning says is not allowed under current rules. A published city proposal would allow attached units, but it has not been adopted.
What about Decatur, Sandy Springs and the other cities?
Each city has its own code. Decatur allows an ADU combined with a garage, with total floor area up to 1,000 sq ft. Sandy Springs' development code allows a guest house over a garage when it meets the location and size standards. In Marietta and East Point, we confirm the current rules with the city for your parcel. See the area pages for detail.
What does a garage need to become a home?
Garages are built for cars, so most need real work to meet residential code:
- A structural check of the slab, footings and walls.
- A vapor barrier and a raised or leveled floor over the slab.
- Wall, ceiling and floor insulation to meet the energy code.
- Framing in the vehicle door opening and adding windows and an entry door.
- New plumbing for a kitchen and bathroom, tied to the sewer line.
- Electrical capacity for the new unit, sometimes a panel or service upgrade.
- Heating and cooling, often a ductless mini-split.
What if the garage is too close to the property line?
Older garages often sit tight to a side or rear line. Whether an existing structure in that spot can be converted, or must be moved or rebuilt, is a question for the zoning code that applies to your lot and the building code's fire separation rules. We answer it during the lot check, before you spend money on drawings.
When is rebuilding better than converting?
When the slab is cracked or out of level, the walls are too short for a legal ceiling height, or termite and water damage run deep. In those cases, the cost of fixing the old shell can approach the cost of a new detached ADU, and a new build gives you a better layout.
What will converting my garage cost?
Nationally, Angi puts garage-to-ADU projects at roughly $60,000 to $150,000. We did not find a reliable Atlanta-only figure as of October 2026. Plumbing distance to the sewer and the condition of the slab move the number the most. See the Atlanta ADU cost guide.