Cause 1: Expansive Clay Soil
Our clay soil swells when wet and shrinks when dry. That movement pushes and pulls on the concrete above it. A slab without proper sub-base preparation is essentially sitting on a moving foundation. Over wet-dry cycles, the movement causes cracking. Proper sub-base and reinforcement are the defense.
Cause 2: Poor or Missing Sub-Base
The sub-base — the compacted gravel or sand layer under the concrete — is what gives the slab a stable foundation. Skip it or do it poorly, and the concrete has nothing solid to rest on. It settles unevenly and cracks. This is the #1 corner contractors cut to lower their bid.
Cause 3: Missing or Misplaced Control Joints
Control joints are the deliberate grooves cut into concrete that tell it where to crack. Without them, concrete cracks randomly wherever it wants. With properly spaced and placed joints, cracking (when it happens) follows the joints — controlled and less visible.
Cause 4: Drainage Problems
Water is concrete's enemy. If water channels under a slab — from poor grading, downspouts dumping near the concrete, or a high water table — it erodes the sub-base and the slab loses support and cracks. Fix drainage first, always.
Cause 5: Improper Mix or Curing
Concrete that's too wet (too much water in the mix) is weaker and more prone to cracking. Concrete that cures too fast (in hot, dry, windy conditions) develops surface cracks. Proper mix design and curing practices — keeping the surface moist during initial curing — prevent these issues.
How We Prevent Cracking
Proper sub-base matched to your soil. Correctly placed control joints. The right mix and reinforcement. Drainage designed to move water away. Proper curing. We can't promise zero cracks — no honest contractor can — but we can dramatically reduce random cracking and make sure the concrete that does crack does so in controlled, managed ways.