Concrete driveways crack mainly because concrete shrinks as it cures and moves with temperature, and because the ground underneath can shift or lose support. Some cracking is normal, but the type, size and location of a crack tell you a lot about whether it matters.
Not every crack is a warning sign. Below are the most common causes, how they look and when a crack deserves a closer look.
Shrinkage and Temperature Movement
Fresh concrete contains water. As it cures, the slab loses moisture and shrinks slightly. That movement creates stress, and if the stress has nowhere to go, the concrete relieves it by cracking.
Control joints are placed in driveways to give that cracking a planned place to happen. When joints are spaced and cut appropriately for the slab, most shrinkage cracks follow them. Thin, hairline cracks between joints are common and are often cosmetic.
Daily and seasonal temperature changes cause the slab to expand and contract as well. Over many years, that repeated movement can open small cracks or widen existing ones.
Settling and Soft Spots Below
Cracks that come with uneven sections usually point to a support problem. If part of the base was loosely compacted, washed out by water or disturbed by roots, the concrete above can lose support and sink. One side of the crack ends up higher than the other.
Heavy rain makes this more likely when water runs along the edges of the driveway or collects under it. Downspouts and poor grading are frequent culprits on residential lots.
Weight and Edge Stress
Driveways are designed around expected use. Large trucks, delivery vehicles, dumpsters or equipment can put more load on the slab than it was built for. Corners and outer edges are usually the first places to break because they have less surrounding support.
If you see cracks forming in a corner pattern or along the edge where vehicles turn, the load and the edge support are worth considering together.
When a Crack Needs Attention
Keep an eye on cracks that:
- keep getting wider over time,
- have one side higher than the other,
- let water flow into them during storms, or
- come with sinking, crumbling or broken pieces.
Those signs can mean more is happening than normal shrinkage. The right fix depends on the cause. Some cracks can be sealed or repaired, while widespread settlement may call for leveling or replacing a section. Our concrete driveway work starts with understanding why the slab cracked, so the solution matches the problem.
No driveway is crack-proof. Good base preparation, drainage, joint planning and proper curing reduce the risk and help keep cracks small and controlled. Those steps matter far more than any single product.
If cracks in your Burlington driveway are growing or making the surface uneven, we can take a look and help you decide whether repair makes sense.
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