Quality 1st Basement Systems repaired this sinking concrete in Trappe, PA by using PolyLevel Injections. We got to the source of the problem which is the soil underneath the concrete slab. Over time, soil becomes to wet, too dry or overall is poorly compacted and cannot support the weight of a heavy slab. When this occurs, the slab begins to sink. PolyLevel is an environmentally friendly, waterproof, polyurethane foam that fills the voids between the slab and soil and lifts it back towards its original position.