Building Underground in Atlanta: What’s Actually Possible?

If you live in or around Atlanta, Georgia and you’re wondering whether you can build underground – a basement, storm shelter, wine cellar, or even something more ambitious – the short answer is yes, you can. But in Atlanta, underground construction comes with very specific challenges, rules, and practical limits.

This guide walks through how underground building works in Atlanta, what’s allowed, and what you should consider before you start planning.

How Common Is Underground Construction in Atlanta?

In the Atlanta area, partial or full basements are very common, especially in single-family homes and townhomes. You’ll also find:

• Underground parking garages in Midtown, Buckhead, and Downtown
• Below-grade storage and mechanical rooms in commercial buildings
• A few tunnels and underground corridors, especially in older downtown developments

What you won’t see much of in Atlanta are large, interconnected underground cities or multi-level residential bunkers. That’s mainly because of soil conditions, groundwater, and cost, not because they’re completely forbidden.

Key Factors That Affect Underground Building in Atlanta

1. Atlanta’s Soil and Bedrock

The Atlanta region sits on what many contractors call “Georgia red clay”, part of the Piedmont geologic region. This matters for underground construction because:

• Clay soils can hold water and expand/contract with moisture changes
• Some neighborhoods have shallow bedrock, which can make deep excavation difficult and expensive
• Sloped lots common in Intown Atlanta (like in Candler Park, Grant Park, and Virginia-Highland) can be good for daylight basements, where one side is underground and another opens to grade

Because of this, most residential underground work in Atlanta stays to one level below grade and focuses on proper drainage rather than extreme depth.

2. Groundwater and Drainage

In Atlanta, water management is often the biggest technical issue for basements and underground spaces.

Problems builders plan for:

• Hydrostatic pressure (water pushing against basement walls)
• Seepage where walls, joints, or slab meet
• Drainage around older homes that were never designed for finished basements

To address this, typical Atlanta builds include:

• Perimeter footing drains (French drains) around foundation walls
• Sump pumps in low points
• Exterior waterproofing membranes and/or drainage boards
• Grading the yard so water flows away from the house

If you’re thinking about finishing or adding a basement in Atlanta, plan to spend a meaningful portion of the budget on waterproofing and drainage.

3. Local Climate Considerations

Atlanta doesn’t have to deal with frost depths like northern states, but its humid, rainy climate still affects underground spaces:

• Higher risk of humidity and mold in poorly ventilated basements
• Need for good HVAC design and dehumidification
• Occasional heavy storms that can test drainage systems

If you’re creating an underground living space or office, make sure the design includes:

• Adequate ventilation or mechanical air exchange
• Reliable dehumidification
• Durable moisture-tolerant finishes (especially for floors and lower walls)

What Types of Underground Construction Are Typically Allowed?

In Atlanta and surrounding areas, most underground projects fall into a few common categories.

Basements in Single-Family Homes

Basements are generally allowed in Atlanta, subject to zoning, setbacks, and building codes. They may be:

• Unfinished storage basements
• Finished basements with bedrooms, living areas, or home theaters
• Walk-out (daylight) basements on sloping lots

To be used as habitable space or bedrooms, basements must meet code requirements like:

• Ceiling height minimums
• Emergency egress (usually a door to the outside or egress windows)
• Proper smoke and carbon monoxide alarms
• Compliant electrical and mechanical systems

Underground Parking and Garages

Many Atlanta multi-family and commercial projects include underground parking, especially in zones where land is limited or height is restricted. These are evaluated as part of the overall site and building permit.

Homeowners sometimes ask if they can create:

• A tuck-under garage in a basement
• A small below-grade parking area on a sloped lot

Both can be possible, but they must meet:

• Driveway slope and access rules
• Stormwater and drainage requirements
• Structural and fire code standards for garages

Storm Shelters and Safe Rooms

Underground storm shelters are less common in metro Atlanta than in parts of the Midwest, but they do exist. In this area, people more often:

• Use interior safe rooms above ground, or
• Convert a portion of a basement into a reinforced safe space

An underground shelter in Atlanta will still require:

• Proper permitting
• Ventilation
• Safe access and egress
• Compliance with local and state building codes

Utility and Service Spaces

Larger buildings around Downtown, Midtown, and Buckhead routinely have:

• Basement level mechanical rooms
• Electrical and communication rooms
• Storage and back-of-house spaces below grade

These are standard and allowed, but are tightly regulated from a fire, structural, and life-safety perspective.

Where Does Atlanta Draw the Line?

There isn’t a single “underground building” law, but your project may run into limits from:

• Zoning regulations (how many stories, how much lot coverage, how close to property lines)
• Building codes (safety, structural, fire, and egress rules)
• Stormwater and environmental rules
• Utility easements (you can’t build over certain buried lines or rights-of-way)

Very large-scale underground projects (multi-level bunkers, extensive tunnels between properties, or commercial spaces entirely underground with limited exits) will face heavy scrutiny and may not be practical, even if not outright banned.

Permits and Approvals: Who Regulates Underground Building in Atlanta?

If you want to build underground in Atlanta, expect to work with more than one office. Here are the key players.

City of Atlanta – Office of Buildings

For projects inside city limits, underground construction is generally reviewed by the:

City of Atlanta Office of Buildings
Atlanta City Hall
55 Trinity Avenue SW
Atlanta, GA 30303
Main line (through ATL 311): 404‑546‑0311

They handle:

• Building permits for new construction, additions, and major renovations
• Review of plans for basements, retaining walls, and structural changes
• Verification that work meets state and local building codes

Zoning and Land Use

Zoning rules will determine what kind of underground space is allowed on your lot. Within the city, zoning is overseen by:

City of Atlanta Department of City Planning
Same City Hall address as above

They review questions like:

• Is this type of structure allowed in your zoning district?
• Does the design meet setbacks, height limits, and lot coverage rules?
• Are parking and access requirements satisfied?

Fulton County and Other Surrounding Counties

If you’re just outside Atlanta (for example in unincorporated Fulton County, DeKalb County, or Cobb County), you’d work with the relevant county Planning and Community Development or Building Department instead of the City of Atlanta. Each has its own permitting process but follows similar state-level codes.

Utilities and Right-of-Way

Before digging deeply in Atlanta, it’s critical to:

• Locate underground utilities (gas, electric, water, communications)
• Respect any easements recorded on your property

In Georgia, utility location typically goes through the Georgia 811 “Call Before You Dig” system. For private property, your contractor may also use private utility locating services.

Safety, Code, and Design Considerations

Structural and Soil Engineering

For anything beyond a simple crawlspace or standard basement, you’ll likely need:

• A geotechnical (soil) report to understand soil bearing capacity, groundwater, and stability
• A structural engineer to design retaining walls, slabs, and waterproofing details

This is especially important if:

• You’re on a steep lot (common in many Atlanta neighborhoods)
• You want tall basement walls or a walk-out at the rear
• You’re building under an existing structure

Fire and Life Safety

Underground spaces must meet strict life safety standards, including:

• Sufficient and clearly marked exits
• Fire-rated walls and doors where required
• Proper ventilation and smoke control
• Compliant stairs and handrails

For residential basements, the most common issues are:

• Missing or non-compliant egress windows in basement bedrooms
• Inadequate smoke/CO detectors
• Insufficient headroom

Moisture, Air Quality, and Comfort

In Atlanta’s climate, comfortable and healthy underground spaces usually require:

• Continuous or controlled mechanical ventilation
• Sealed foundation walls and slabs
• Effective insulation (often on the exterior of foundation walls or interior with vapor-smart strategies)
• Regular use of a dehumidifier or an HVAC system designed for the space

Neglecting these can lead to musty odors, mold growth, and long-term damage.

Typical Underground Options in Atlanta: A Quick Comparison

Below is a simple overview of what Atlanta property owners usually consider and what’s involved.

Special Considerations for Historic or In-Town Properties

If you own a home in one of Atlanta’s historic neighborhoods (such as Inman Park, Grant Park, or parts of Midtown), or in a designated historic district:

• You may face design review for exterior changes
• Altering foundations or adding visible walk-out basement doors and windows may require additional approvals
• Traditional homes may not have been designed for significant excavation next to existing foundations

In these areas, architects and engineers often look for lower-impact solutions, like:

• Partial excavation
• Interior reconfiguration
• Careful underpinning and staging to avoid damage to neighboring structures

Practical Steps if You Want to Build Underground in Atlanta

If you’re seriously considering an underground project, these steps usually make sense:

1. Check your property’s zoning.
   Identify your zoning district (for city residents, through the City of Atlanta Department of City Planning) and review basic rules on usage, setbacks, and parking.

2. Consult a local architect or designer.
   Choose someone familiar with Atlanta’s codes, soils, and permitting process, especially if you plan more than a simple storage basement.

3. Engage structural and/or geotechnical engineers if needed.
   This is essential for deeper basements, retaining walls, steep slopes, or building beneath existing structures.

4. Plan for drainage and waterproofing from the start.
   Don’t treat waterproofing as an afterthought; integrate it into the design, detailing, and budget.

5. Obtain proper permits.
   Work with licensed professionals to submit drawings to the City of Atlanta Office of Buildings (or your local county, if outside city limits).

6. Coordinate utility locates.
   Before excavating, ensure all utilities and easements are identified.

7. Budget realistically.
   In Atlanta, going underground is typically more expensive per square foot than building above grade, especially once you include waterproofing, retaining walls, and specialized engineering.

So, Can You Build Underground in Atlanta?

Yes. Basements, underground parking, storage, and even specialty underground spaces are all possible in Atlanta and are already in use across the city. What’s realistic for your property depends on:

• Your location and zoning
• Lot slope and soil conditions
• Your budget
• How you plan to use the underground space

With proper planning, engineering, and permits, underground construction can be a safe and effective way to add space in Atlanta—but it needs to be approached with local conditions and regulations front and center.