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Where Can I Build An ADU In Atlanta?

Updated: Jun 13, 2023

Whether you hope to build an ADU in your backyard, or you’re looking for a home that is ‘ADU friendly’, the first question to ask is, “Can I legally build an ADU on this property?” Before getting lost in designs and dreams of becoming an ADU influencer, there are a few important, less glamorous steps to address first. We’ll lay out each of those steps here, but if you aren’t interested in the DIY approach, ATL ADU CO will handle everything from start to finish!

The first step is determining what municipality your home (or potential home) is located in. Every municipality in Metro Atlanta has its own Geographic Information System (GIS), to determine zoning, and Municipal Code, or “Municode”. At ATL ADU, the primary municipalities we work in are City of Atlanta, Dekalb County, City of Decatur, and City of Avondale. The focus of this post is the City of Atlanta.

Once you have confirmed your governing municipality, the next step is to determine your zoning via GIS. Your ADU dreams start (or end), with your residential zoning. In the City of Atlanta, you can build an ADU, by right, up to 750 square feet, in zones R-4, R-4A, and R-5. The good news is that those zones make up over 60 percent of the residential zoning in Atlanta. In Dekalb County and City of Decatur, all “R’s” allow for ADUs, and in Avondale Estates an ADU may be added to an R-12 or R-24 zoned lot.

In the City of Atlanta, you can build an ADU in zones R-4, R-4A, and R-5, which make up over 60 percent of the residential zoning.

The next key piece of information is the setbacks in your zoning, which can determine whether you have enough space or not. In the City of Atlanta, zones R-4 and R-4A have a seven foot side setback and fifteen foot rear setback. R-5 has more favorable setbacks at just four feet to the side and rear property lines. Our smallest unit, the East Lake, is 308 square feet, with a footprint of 22’ x 14’. That would require the front of your ADU to be 29 feet from the rear property line in R4. So any backyard measuring less than 40 feet from the primary home to the rear property line will be tight (unless zoned R-5). The City of Atlanta does not require a minimum distance between the primary and accessory structure, which comes down to owner preference.

This property is zoned R-5, which provided enough space for the owner to max out their ADU at 750 sft thanks to minimal side and rear setbacks.

There are also intangible factors to consider that aren’t deal breakers, but can impact your cost or buildable space. A flat lot with no trees makes things easier, and likely less expensive. Being on an alley means you can measure rear setbacks from the middle of the alley, rather than the rear property line, which provides additional space. And if the alley is usable, that’s an added bonus, because your guests have their own private entry. A corner lot can also be advantageous in that it provides a more private side entry point and street parking spot. One downside to a corner lot, however, is the corner lot side setback, which measures half the front yard setback (30-35’) in the City of Atlanta. Location is also important when determining if a property is a good fit for an ADU.

This ADU is on a corner lot, which is advantageous with parking/entry on different streets. The downside was the owner preferred the 2bd unit, but only had room for the 1bd unit due to the corner lot (street) side set back.

If you are an investor, or a realtor with an investor client, looking to purchase a home then build an ADU, you should limit your search to the City of Atlanta. That is because the City of Atlanta allows you to rent both the primary home and the accessory home. Dekalb County, for example, requires the homeowner to live in either the primary or the accessory structure, which of course rules out an investor who doesn’t live on the property. With all these factors in mind, you could say the ideal property for an ADU is located in the City of Atlanta, zoned R-5, with a deep lot (150+ feet), on an alley or corner, that is relatively flat with very few trees or neighboring boundary trees, and is close to transit in a walkable neighborhood. If your realtor can find that property, they have earned their commission!

You could accomplish everything mentioned to this point from your computer. But confirming the municipality, zoning, setbacks, buildable area, and trees only gets you about fifty percent of the way there. A survey and site plan is a critical piece of information, and it’s impossible for a homeowner or investor to determine feasibility without this step. With a survey in hand, a CAD generated site plan can be done to mark things like setbacks, tree critical root zones, lot coverage, and floor area ratio (FAR). Other constraints might include things like Historic Districts, SAPs (Special Administrative Permits), or Conditional Zoning. A survey and site plan would need to be hired out, and that gets you to roughly 90% feasibility - nothing is 100% certain until you have a permit in hand! To date, we have never completed our feasibility phase and not received a permit, but it is still worth noting.

Here is the site plan for a future 1bd / 1ba 'RTown' ADU currently in the COA permitting process. This property benefits from a deep lot, accessible alley, and minimal tree impact.

If you choose to go the DIY route, other hurdles, along with zoning and permitting, will include finding an architect who is familiar with ADUs, finding a contractor who is able/willing to build small, and finding time to become a project manager. If this sounds daunting to you, ATL ADU is a turnkey solution to all of these challenges. Our service includes everything from surveying, zoning, site planning, obtaining permits, project management, and construction - all the way to the certificate of occupancy. All our clients have to do is choose a predesigned model, the orientation of that model in their backyard, and the exterior paint color! For a free consultation, contact us here!

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