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setting and uneven concrete

What is Slab Settlement?

Concrete slabs inside and outside your home can settle for various reasons, but they all are tied to the soil under your home. Learn more here.

setting and uneven concrete

Simply stated, slab settlement is the movement a concrete slab experiences when the soil below can no longer support the weight of it. Most likely the soil changed. While there are many reasons the soil may change underneath your concrete slab, there is one common reason: changes in soil’s moisture content.

Two very common soil types are sandy and clay soil. 



Moisture does not have a big effect on sandy soil. When sand gets wet it doesn’t expand in size, and when it is dry it doesn’t shrink. But sand does wash out.


When clay is wet, it holds onto the water and expands in size. When it is dry, it shrinks. Imagine how dramatic this is when several feet of clay soil exist below your concrete slab– whether it be your driveway, patio, or beneath the concrete floor in your home!

Soil can dry out for several reasons, including drought conditions, tree roots drawing valuable moisture from the soil, and leaking HVAC systems under your floor slabs. In any case, as the soil beneath your concrete slab shrinks in size, it creates an empty space for the slab to settle into. The result? Cracked and unlevel concrete.

Conveniently, Tar Heel Basement Systems provides a non-disruptive solution for your sinking slab called, PolyRenewal™. To learn more about PolyRenewal™ or to schedule your free estimate appointment, call our office.

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