For a Marietta driveway that carries everyday cars, the trade publication ConcreteNetwork.com calls 4 inches of concrete a sufficient minimum, and suggests 5 or 6 inches for heavier loads. Treat those as general guidance, not a local rule. The right thickness for your driveway depends on what drives on it and what sits under it.
The Short Answer for Marietta Driveways
If only standard passenger vehicles will use the driveway, general guidance starts at 4 inches. If truck traffic or a large RV will use it, the same guidance moves up to 5 or 6 inches.
That is the whole answer in two sentences, and it is also where the real conversation starts. A thickness figure means little on its own. It works only when the ground underneath is prepared, the edges are supported and water has somewhere to go.
JJC Concrete is a family owned concrete company based in Marietta, pouring concrete in Cobb County and across metro Atlanta since 2010. Driveways are part of the residential work we do, alongside patios, walkways and garage slabs.
Where the Common Thickness Figures Come From
You will see a lot of numbers online. It helps to know who published them and what each one was written for.
Trade guidance for residential driveways
The 4 inch and 5 to 6 inch figures above come from ConcreteNetwork.com, a trade publication for concrete work. It describes 4 inches as enough for a residential driveway serving a standard passenger vehicle, and it frames the range for driveways as 4 to 6 inches or more. It also notes that most codes for residential driveways set a 4 inch minimum. It is a trade source, not a Marietta rule, so read the figures as industry guidance.
What ACI says about light vehicle pavement
The American Concrete Institute publishes ACI 330R-08, a guide for designing and building concrete parking lots. It is written for parking lots, not home driveways, but one line applies directly to a driveway that sees only cars. The guide says slabs for facilities serving only light vehicles may have thicknesses "influenced by the practical limitations of the material and environmental effects rather than by the pavement stress created by vehicle loads."
In plain words, a car alone is not what sets a light duty slab's thickness. The material itself and the conditions it lives in (weather, water, the ground below) carry at least as much weight in the decision.
The 3 1/2 inch figure in the residential code
Some people quote 3 1/2 inches. That number comes from the model International Residential Code, section R506.1, which says concrete slab on ground floors shall be not less than 3 1/2 inches thick. Georgia uses the International Residential Code, 2024 Edition, with Georgia amendments, as its state minimum standard, according to the Georgia Department of Community Affairs. Georgia's amendments can change a code section, so confirm the current rule with your building department.
That section covers floors, such as a garage floor slab. It is not a driveway rule, and a minimum for a floor is not a target for a driveway that carries vehicles in and out every day.
What Changes the Right Thickness for Your Driveway
Here are the questions that move the number up or down on a real job.
- What drives on it. Cars only, or also truck traffic or a large RV? For those heavier loads, the general guidance moves up to 5 or 6 inches.
- Where heavy loads sit. An apron at the street or a turnaround pad where a truck parks can carry more load than the rest of the driveway. Some plans thicken those areas.
- The ground underneath. A slab rests on its subgrade. Soft spots, loose fill or uneven support below can undo a good thickness above.
- Water. ACI 330R-08 notes that concrete surfaces drain well with only minimal slopes. Even so, water still needs a path away from the slab and away from the ground that supports it.
- Edges. How the edge of the slab is supported, especially where tires run off the side, deserves the same attention as the middle.
None of these questions has a single right answer for every home in Marietta. That is why a thickness gets set for the driveway in front of you, not pulled from a chart.
Thickness Is One Part of a Driveway That Holds Up
A thicker slab poured on poor preparation is still a slab on poor preparation. Thickness works together with three other things.
Base and subgrade
The soil is graded and compacted, and many plans call for a compacted gravel base under the concrete. The goal is uniform support, so the slab is not bridging over soft spots.
Joints
Concrete shrinks as it cures and moves with temperature. Control joints give that movement a planned place to crack, in a straight line, instead of a random one across the middle of a panel.
Reinforcement
Some driveways include steel reinforcement or fibers. Whether a driveway needs it, and what kind, depends on the loads and the ground, and it is worth talking through before the pour instead of after.
Does Marietta Set a Required Driveway Thickness?
Check with the City of Marietta or Cobb County for any thickness rule that applies at your address, especially where a driveway meets the street.
Permit requirements are set by the city or the county, depending on where you live. Ask about permits for your project when you call, and check with the City of Marietta or Cobb County for your address.
Replacing an Old Driveway in Marietta
Some driveway projects start with an old slab that has cracked, settled or broken apart. Our driveway work includes tearing out and hauling off the old concrete, and concrete removal and replacement is one of the services we offer.
Replacement is also the moment to revisit thickness. If the old driveway was poured for a sedan and now sees a truck and a trailer, the new one does not have to repeat the old decision. See how driveway work in Marietta fits with the rest of our local services, or read more about our concrete driveway service and removal and replacement.
Frequently Asked Questions
Is 4 inches thick enough for a concrete driveway?
For a driveway that serves passenger cars, ConcreteNetwork.com describes 4 inches as a sufficient minimum. For truck traffic or a large RV, the same guidance suggests 5 or 6 inches. The ground preparation under the slab matters as much as the thickness itself, so consider both together.
Is there a code thickness for driveways in Georgia?
Georgia uses the International Residential Code with state amendments. In the model code, section R506.1 sets 3 1/2 inches as the minimum for concrete slab on ground floors, which covers floors, not driveways, and Georgia's amendments can change that section. For any thickness rule that applies to a private driveway at your address, check with the City of Marietta or Cobb County.
Should my driveway be thicker where the garbage truck or delivery trucks turn?
Areas that carry heavier loads, like an apron at the street or a turnaround pad, can take more stress than the rest of the driveway. Some plans thicken those areas. Tell us what vehicles use the driveway so the thickness fits the real traffic.
Do you pour driveways in Marietta?
Yes. JJC Concrete is a family owned company based in Marietta and has poured concrete since 2010. Driveway work includes tearing out and hauling off old concrete. We are licensed and insured, and hablamos español.
Get a Free Estimate for Your Marietta Driveway
If you are planning a new driveway or replacing an old one in Marietta, tell us what drives on it and what the current slab is doing. Call (770) 755-2622 or use the estimate form on our contact page for a free estimate.