Voids beneath concrete slabs can be filled with two component polymer foam designed to work in wet or dry conditions. AP Lift 430 foam can support up to 7,200 lbs per square foot and will cure to 90% full strength in 15 minutes. (Of the most resilient concrete slab jacking foams, AP Lift 430 is proven to lift concrete slabs under harsh conditions. This two-component, high-strength, high-density, hydro-insensitive structural polyurethane foam is the top slab jacking solution for concrete slab foundation repair, soil stabilization, and compaction grouting. AP Lift 430 weighs 2.75 – 3.25 pounds per cubic foot.)
Polyurethane foam conforms to void shape more accurately than cement grout, and - unlike cement - it doesn't shrink or sink over time.
The video below depicts a real time example of void fill and slab stabilization. A residential driveway is undermined by a large void. Because an entire bank of soil washed away on one side of the slab, we get an unusually clear view of polyurethane void fill in action.
Observe the process closely and let us know if you have any follow up questions. We have the most knowledgeable and helpful customer support in the industry, so don't hesitate to call us at 404-618-0438 after you've watched this video!