Driveway cracks get treated as one problem with one solution, which is why so many of them get filled, covered and then reappear. There are six of them worth telling apart, they have different causes, and three of the six mean something entirely different about the future of the slab.
You can classify your own in about ten minutes with a straight edge and a fingernail.
The six driveway cracks you will actually see
Map crazing. A fine, shallow network across the surface, like a dried lakebed. It comes from the surface drying faster than the concrete beneath it during the original finishing, usually because the day was hot, windy or both. It is millimetres deep. It has nothing to do with the strength of the slab and an overlay covers it permanently.
Shrinkage cracks. Thin, wandering cracks that appeared in the first year and have not changed since. Concrete shrinks as it cures and relieves that stress somewhere. If they are stable and level across, they are a closed chapter.
Cracks on the joint lines. A crack that runs dead straight and either lines up with a saw cut or completes the line between two of them. That is the slab cracking where it was always going to crack, at a place the joints did not cover, either because they were cut too shallow or spaced too far apart. It is not a defect in the concrete. It is a joint that arrived late, and it has to be treated as a joint from now on.
Load cracks. Cracking concentrated where the heaviest weight goes: the apron at the street, the wheel tracks, the turning area. Usually caused by a slab that was poured thinner than the traffic deserved, or by a base that was never compacted properly, or by something far heavier than a car being parked or delivered. Look for a pattern that matches where vehicles actually sit.
Settlement cracks. The ones that matter. A crack with a height difference across it, or one that is wider at one end, or one that has visibly opened over a few seasons. The ground under one side has moved. In this part of Georgia the usual causes are water getting under the slab through open joints and washing the fine material out of the base, or clay subgrade swelling and shrinking through the wet and dry cycle, or both together.
Edge and corner cracks. Breaking away at the edges of the drive, at the apron, and at corners. This is often not a slab problem at all, it is a lack of support at the edge, and it is common enough to have its own treatment in edges and the apron.
The test that separates the serious from the cosmetic
Lay a long straight edge across the crack, perpendicular to it, with the ends resting on sound concrete either side. Then look at it from ground level.
If both sides are level and the straight edge sits flat, the slab is still supported on both sides of the crack. Whatever caused it, the ground is doing its job. That is a repairable crack.
If one side sits lower and you can see daylight under one end of the straight edge, the ground under that side has moved. Filling the crack changes nothing about that. The crack is a symptom, and the cause is under the concrete where you cannot see it. That reading is the first step of resurface or replace.
Do this at every significant crack on the drive, not just the worst one. A drive with one settled section and five stable cracks is a very different job from one where every crack has a step in it. Take a photograph of each straight edge test as you go, because the pattern across the whole drive is the thing an estimator needs, and it is far more useful than a photograph of the single crack that annoys you most.
Why cracks come back through a new surface
Reflective cracking is the most common visible failure in driveway resurfacing, and it is entirely preventable. A crack that is still moving, seasonally or under load, will keep moving after an overlay goes over it. The overlay is bonded to both sides, so it gets torn apart along exactly the same line, and within a season the old crack pattern is showing through the new surface.
The prevention is not a better product. It is treating working cracks as joints: routing them out, filling them with something that can move, and carrying them up through the new surface where they are cut in and sealed rather than bridged. A resurfaced driveway should still show joints. See how cracks are treated during resurfacing for where this sits in the sequence.
What is not a crack
Two things get reported as cracking that are not. Surface scaling and spalling is loss of the concrete surface itself, leaving a rough sandy texture and exposed aggregate, and it has different causes and a different repair from anything else on this page. Popouts are small sharp craters with a piece of stone at the bottom, caused by a reactive or porous aggregate near the surface, and they are isolated and cosmetic.
Cracking around a pool follows different rules again, because the driver there is water at the coping joint rather than vehicle load. That is set out in cracks on a pool deck.
So what does each one need
| Crack type | What it needs |
|---|---|
| Map crazing | Nothing structural. Covered by an overlay. |
| Stable shrinkage cracks | Rout, fill, grind flush. Then overlay if wanted. |
| Cracks on joint lines | Treat as a joint. Carry through any new surface. |
| Load cracks | Understand the load first. Repair may not hold without it. |
| Settlement cracks with a step | Deal with the ground. Surface work alone will fail. |
| Edge and corner breakup | Restore support at the edge, then rebuild the edge. |
For most readers the answer is concrete crack repair and, once that is done, driveway resurfacing to renew the surface across the whole drive so the repairs are not the most noticeable thing about it.
What to have ready when you call
Photographs taken straight down in flat light rather than bright sun. A note of which cracks have a step across them, from the straight edge test. Roughly when the driveway was poured and whether it has been repaired before. Where water sits after rain. And whether anything unusually heavy has been on it: a dumpster, a delivery, a trailer parked on a jack for a while.
That handful of facts turns a guess into a scope, and it changes the conversation from what a contractor thinks you need into what the drive is actually doing. The short answers to the most common versions of this question are in answers to the questions we get most.
Frequently asked questions
Are cracks in a concrete driveway normal?
Some are. Concrete shrinks as it cures and it will crack somewhere unless joints are cut to control where. Fine surface crazing and thin stable cracks that appeared early and have not changed since are normal and cosmetic. Cracks that are still changing, that have a height difference across them, or that are wide enough to catch a finger are telling you something else.
How can I tell if a driveway crack is serious?
Lay a straight edge across it. If both sides are level, the crack is a surface or shrinkage issue and the slab is still supported. If one side sits lower than the other, the ground under that side has moved, and no amount of filling will change that. The straight edge test takes a minute and it separates the cosmetic from the structural better than crack width does.
Why do cracks keep coming back in the same place?
Because the cause is still there. A crack that reappears after being filled is a working crack: the slab is moving at that line, seasonally or under load, and the filler is being torn apart. The fix is to treat it as a joint, which means routing it out and filling it with something flexible that can move, rather than something rigid that cannot.
Does clay soil cause driveway cracking in Georgia?
It contributes. Clay subgrade swells when it takes on water and shrinks when it dries, and that cycle moves whatever is sitting on it. Combine it with water getting under the slab through open joints and cracks, which washes fine material out of the base, and you have the most common structural cause of driveway cracking in this part of the state.
Can cracked concrete be resurfaced?
Yes, provided the cracks are classified and treated correctly first. Static cracks are routed, filled and ground flush and then disappear under the overlay. Working cracks have to be carried through the new surface as joints. Cracks with a height difference across them mean the ground is moving, and that has to be dealt with before any surface work is worth doing.