Types of ADUs in Atlanta: Detached, Garage, and Prefab Options
Types of ADUs and Associated Regulations
Atlanta allows a variety of ADU types
One of the best parts about building an accessory dwelling unit (ADU) is the flexibility it offers. Whether you’re thinking about a stand-alone guest house, a basement apartment, or converting your garage into livable space, Atlanta allows a variety of ADU types—as long as they meet the city's zoning and building code requirements.
At Heide Contracting, we help you choose the ADU style that fits your property, lifestyle, and long-term goals. We evaluate each site individually, balancing code compliance with creative design to ensure your space is both beautiful and fully functional.
But don’t forget to look down! Atlanta’s ADU rules provide a hidden opportunity: basements and crawl spaces can often be converted into living space without affecting your lot’s zoning limits. Since most underground space is excluded from FAR calculations, this option offers maximum usable square footage—without a visible footprint!
Here’s a look at the most common types of ADUs in Atlanta—and what the city requires for each:
Detached ADUs
Standalone living units
What they are: Standalone living units located separately from the main house—often in a backyard or rear corner of the lot.
Key regulations:
Must follow a 750 square foot size limit
Must adhere to maximum height of 20 feet
Cannot exceed 25% of rear yard coverage
Must maintain 4-foot setbacks from side and rear property lines
Subject to FAR and lot coverage limits for the entire property
Why homeowners love them: Detached ADUs offer the most privacy and are ideal for long-term rentals, aging-in-place suites, or independent living spaces for family members.
Attached ADUs
What they are: Units physically connected to the main home, often via an addition, over a garage, or as a side wing.
Key regulations:
Still subject to the 750 square foot size limit
Typically required to match the architectural style of the main home
Must share utilities (water, sewer, electrical) with the primary residence
Must comply with all setback and height requirements
Why homeowners love them: Attached ADUs maximize space while minimizing the impact on the lot. They’re a great choice when outdoor space is limited or when you want easy access between the main house and the ADU.
Garage and Basement Conversions
Underground ADU interior
What they are: Existing garages or unfinished basements that are converted into fully livable, self-contained units.
Key regulations:
Must meet all ADU codes, including egress, ventilation, and ceiling height
Basement ADUs may require waterproofing, insulation, and fire safety upgrades
Garage conversions must maintain structural integrity and often need flooring, insulation, and new utility connections
Why homeowners love them: Conversions are typically more cost-effective than new builds and make great use of existing square footage. They’re especially popular in urban neighborhoods where lot size is tight.
Bonus: Underground space doesn’t count toward FAR.
In most cases, Atlanta does not include basements in Floor Area Ratio (FAR) calculations—meaning you can convert or expand below ground without eating into your zoning limits. Our team can help you evaluate options like lowering your basement floor or transforming crawl space into fully functional living quarters.
Prefab and Modular ADUs
What they are: Factory-built units that are transported to the property and installed on a foundation.
Key regulations:
Must meet all the same zoning and building codes as site-built ADUs
Size, height, and setback limits apply just the same
Require foundation preparation, utility hookups, and inspection approvals
Why homeowners love them: Prefab ADUs offer a faster build timeline and streamlined construction process while still delivering high-quality, code-compliant living spaces.
No matter which type of ADU you’re considering, the key to success is understanding what’s possible—and what’s required. At Heide Contracting, we help you evaluate every option, ensuring your ADU is fully integrated with your home’s layout, your property’s zoning, and your long-term needs.
Usage Restrictions: Atlanta ADU Regulations
While accessory dwelling units (ADUs) offer incredible flexibility, there are important rules in place to ensure they remain residential in nature and complement the primary home. At Heide Contracting, we help you plan with these regulations in mind—so your ADU not only fits your needs, but also stays fully compliant for the long term.
Here’s what Atlanta homeowners need to know:
Rental Rules
ADUs can be used as long-term rentals—defined as stays of more than 30 consecutive days. Whether you’re planning to rent to a tenant, offer housing for extended family, or generate passive income, the City of Atlanta supports this type of use.
However, if you’re thinking about short-term rentals (like Airbnb or VRBO), additional regulations may apply. These often include:
Licensing requirements
Occupancy limits
Neighborhood restrictions
We recommend confirming current short-term rental policies with the City of Atlanta or letting our team guide you through the process during your consultation.
Ownership Limitations
Your ADU is considered part of your primary property, which means:
It cannot be sold or deeded separately from the main home
It must remain an accessory use, not an independent parcel
This ensures ADUs support housing flexibility while preserving neighborhood cohesion and zoning intent.
No Commercial Use (Unless Zoned for It)
ADUs are designed for residential use only. That means:
You cannot operate a business or use the ADU as a commercial storefront
Exceptions may apply only if your property is located in a mixed-use or commercial zone and you meet additional permitting criteria
If you're unsure how your zoning impacts ADU use, Heide Contracting is here to help clarify what’s possible—and what’s not—based on your unique property.
Basements Are a Whole Different Story
While all those ADU rules might seem limiting, none of this applies to basements! A basement—especially one converted from an unused crawl space—offers an exciting opportunity to expand your living area without the same rental and zoning restrictions that apply to detached accessory units.
Whether you're dreaming of a guest suite, home office, entertainment zone, or even extra storage, converting your crawl space into a fully functional basement is one of the smartest ways to maximize your property's potential. And best of all? It adds value, comfort, and usable square footage—all without changing the footprint of your home.
At Heide Contracting, we specialize in turning underutilized crawl spaces into beautiful, code-compliant basements tailored to your lifestyle. From structural assessments to waterproofing and finishing touches, our team handles every step with precision and care.
Ready to go below ground and build up your home's future? Let's talk about what’s possible beneath your feet.
Special Considerations for ADUs in Atlanta
Building an accessory dwelling unit (ADU) in Atlanta opens the door to flexibility, added value, and modern functionality—but it also comes with a unique set of rules depending on your property’s location, zoning classification, and surrounding neighborhood.
At Heide Contracting, we don’t just build—we help you navigate every consideration with confidence. From zoning nuances to historic overlay restrictions, we’re here to guide your project from blueprint to final inspection without unnecessary setbacks or surprises.
Here’s what Atlanta homeowners should keep in mind when planning an ADU:
Zoning Compliance
Not every lot is eligible for an ADU, so the first step is confirming that your property is zoned appropriately. In Atlanta, ADUs are permitted in:
R-4: Traditional single-family residential
R-4A: Higher-density single-family
R-5: Duplex and small multi-family zones
Each district has its own setback, height, and lot coverage rules. We handle zoning research and compliance verification up front, so you know exactly what your property qualifies for before any design work begins.
Lot Coverage and Size Limits
To maintain open space and neighborhood character, Atlanta limits the amount of your lot that can be developed:
ADUs must be 750 square feet or less
The combined footprint of your main home and ADU must not exceed 55% of the total lot area
Detached ADUs can cover no more than 25% of the rear yard
We design with these ratios in mind, ensuring your ADU fits seamlessly into the landscape while maximizing usable space.
Height and Setback Requirements
Detached ADUs in Atlanta must adhere to:
A maximum height of 20 feet
Minimum side and rear setbacks of 4 feet
These limitations help protect privacy, maintain sightlines, and preserve the look and feel of surrounding homes. If your property presents challenges—like a sloped yard or tight lot—we’ll find creative, code-compliant solutions to make it work.
Design Standards
ADUs in Atlanta are required to match the architectural style of the primary residence. That includes:
Rooflines and exterior materials
Colors and finishes
Window and door placement
At Heide Contracting, we specialize in cohesive design—so your ADU looks like a natural extension of your home, not an afterthought.
Utility Connections
In most cases, your ADU will need to share utilities with the main house, including:
Water and sewer
Electric and gas lines
Coordinating these connections during the design and permitting phases is key to avoiding costly changes later. We work with licensed plumbers and electricians to ensure everything is up to code—and efficiently installed.
Historic and Overlay District Restrictions
If your property is located within a historic district (like Inman Park or Druid Hills) or a special overlay zone (such as the BeltLine Overlay), you may face additional design and material restrictions. These districts often require:
Specific building materials and roof types
Approval through a Certificate of Appropriateness (COA)
Enhanced guidelines for visibility, setbacks, and scale
Heide Contracting has experience working within these parameters, ensuring your ADU project respects both the neighborhood’s history and your modern-day goals.
Rental Use and Occupancy
Atlanta allows ADUs to be rented as long-term housing, provided they remain accessory to the primary residence. Short-term rentals may be possible, but typically require:
Additional permits
Licensing
Compliance with neighborhood rules
We help clarify what kind of rental use is allowed for your property and ensure the build supports your intended use—now and in the future.
Permitting and Inspections
Every ADU in Atlanta must go through the city’s permitting and inspection process. That includes:
Submitting detailed construction plans
Paying required permit fees
Completing inspections at key construction milestones
With Heide Contracting, you don’t have to handle this alone. We manage the paperwork, coordinate with city officials, and keep your project on schedule—ensuring your ADU is safe, legal, and built to last.
Thinking Outside the Box? Go Below It.
If your property isn’t eligible for an ADU—or if zoning, lot size, or historic restrictions are making it more complicated than you’d like—there’s another smart way to add space and value: a crawl space to basement conversion.
Unlike ADUs, basement conversions aren’t subject to the same zoning overlays, square footage caps, or exterior design restrictions. That means:
No 750-square-foot limit
No detached structure setbacks
No architectural matching requirements
You gain significant usable space within your home’s existing footprint—without the regulatory hurdles that can come with building an entirely separate unit.
At Heide Contracting, we specialize in transforming underutilized crawl spaces into beautiful, code-compliant basements tailored to your lifestyle. Whether you want a home office, gym, guest suite, or playroom, we handle every step—from structural assessments and moisture control to permits and finishes.
Key Benefits of Basement Conversions:
Expand your home without changing its exterior footprint
Avoid complex zoning and overlay district restrictions
Increase your home’s resale value and livable space
Customize for your specific needs—no “one size fits all” limitations
If you're running into roadblocks with an ADU or simply want to explore all your options, a basement conversion could be the hidden opportunity right beneath your feet.
Ready to dig deeper? Let Heide Contracting help you unlock the full potential of your property.
Whether you’re envisioning a backyard cottage, a garage conversion, or a fully finished basement, expanding your living space is about more than just square footage—it’s about making your property work harder and smarter for you.
At Heide Contracting, we bring deep knowledge of Atlanta’s zoning codes, creative design solutions, and construction expertise to every project. From navigating ADU requirements to uncovering the hidden potential beneath your home, we’re here to help you make confident, informed decisions every step of the way.
Ready to explore your options? Let’s talk about what’s possible for your lot, your home, and your future. Reach out for a consultation today—and let’s start building space that fits your life.
