Cracks in Your New Concrete?
How to Tell Normal From Serious

You just paid good money for a new slab and it is already cracking. Before you call your contractor angry, here is the honest answer from someone who pours concrete in Texas for a living: concrete almost always cracks a little.

The question is not whether it cracked — it is which kind of crack you are looking at. Most are nothing. A few mean the slab is moving. Here is how to tell them apart without panicking.

Why Concrete Cracks (Even Good Concrete)

Concrete shrinks slightly as it cures. As the water in the mix evaporates, the paste pulls in on itself and the surface can split into fine lines. We call these shrinkage cracks, and they show up in the first weeks after a pour — even on jobs done exactly right. A hairline shrinkage crack is cosmetic. It does not mean your slab is bad.

That said, a pattern of wide, displaced, or spreading cracks usually traces back to a few things cheap jobs skip: no base excavation or compaction, rebar left lying on the dirt instead of chaired up into the slab, a mix watered down on site so the crew could finish faster, or control joints cut days too late. Shrinkage is normal. A slab full of wide, stepping cracks is not.

The Two Signs It Is More Than Shrinkage

Most shrinkage cracks you can ignore. Two things should actually get your attention — and a quick way to grade the rest:

• Width you can slide a nickel into. A crack wider than about a quarter inch is not normal shrinkage. Something under the slab is moving, or the slab is pulling apart.
• One side sitting higher than the other. Lay a straight edge across the crack. If one side is lifted even a little, the slab is heaving or settling — and that will get worse, not better.

A few more worth knowing: spider or map cracking across a wide area points to a weak surface or scaling; a crack that keeps widening over weeks is active movement; edge pop-outs and exposed aggregate mean a soft surface. But the two that matter most are width and displacement. Either one means the slab is moving. A hairline crack that stays flat and thin is just shrinkage.

Why Texas Clay Changes the Math

Much of South-Central Texas sits on expansive clay. This clay swells when it is wet and shrinks when it is dry, and it does it every season. A slab up north sits on more stable ground; a slab here gets pushed and pulled underneath all year long. Add Texas summer heat that flash-dries the surface and occasional winter freezes, and you have a climate that punishes cheap work.

That movement is exactly why soil prep before the pour matters more than almost anything else — a good base absorbs the clay's movement; a poor base transfers it straight into your concrete. If you are planning a slab for a larger building, the same clay-soil rules apply — see our guide on how thick a barn slab should be in Texas.

What To Do Right Now

Do not fix anything yet. First, document it. Lay a coin or a ruler next to the crack and take a clear photo — the coin gives scale so you can tell later if it has gotten wider. Note the date on the photo. Then watch it for a few weeks.

A shrinkage crack will stay the same. A crack that keeps widening, or one where the two sides start to step, is telling you the slab is still moving. That is when it is time to get it looked at by a real concrete driveway contractor in Seguin.

Repair, Seal, or Leave It Alone

A hairline crack that is not moving often just gets sealed — a flexible sealant keeps water out so it does not widen with freeze-thaw or root growth. A wide crack or a displaced one is a different conversation. Depending on what is going on underneath, that can mean a targeted repair or cutting out and replacing a section of the slab.

The right call depends on what the slab is doing, not what the crack looks like on top. If the surface is sound, sealing alone can be enough — here is how we approach concrete sealing in Seguin. No two cracks are exactly alike, which is why we look at them in person before recommending anything.