Sometimes your concrete can appear to be in pristine condition, but you notice there is a large gap underneath it. This space between the slab and the dirt is called a void! And you definitely want to get it filled in. If you have voids beneath your slab, chances are if it hasn’t sunk and cracked already, eventually it will. Not to mention, sometimes those voids can be home to rodents or other creatures. Trust us, you’ll want to fill it in just in case.
True Level spraying PolyLevel foam beneath a bridge approach to fill a large void.
It is the soil underneath the concrete slab that has caused the settlement. The soil has failed to support the concrete for one of these reason: drying and shrinking soils, wetting and softening of soil, poorly compacted fill soil.