Uniform thickness concrete slabs are sometimes specified for use on expansive soil. They are usually very thick and require more reinforcement, whether post-tensioned cables or rebar, as required by building codes and accepted design practice, in order to provide the necessary reinforcement strength for the large mass of concrete.
When expansive soil expands under a uniform thickness slab it has nowhere to go, so the foundation is pushed upward. Incorporating the Wafflemat System with the uniform thickness slab can reduce concrete volume and the amount of reinforcement, because the Wafflemat foundation efficiently uses these two materials.
Most importantly, Wafflemat absorbs the volume change of the expansive soil. The use of non-expansive fill is not required with Wafflemat.
Uniform Thickness Slab:
Using Wafflemat™ with Uniform Thickness Slab
|With Wafflemat:||Without Wafflemat|
|Absorbs volume change of expansive soil, thereby reducing uplift forces||Expansive soil is in contact with the entire foundation, and pushes the foundation slab upward|
|More efficient use of concrete and reinforcement materials||More concrete and reinforcement materials are required|
|Non-expansive fill is usually not required||Non-expansive fill is used to attempt to reduce uplift forces of expansive soil|