Polyurethane Foam Injection: Lifting Sunken Concrete With Expanding Foam

When the slab is a good candidate and the underlying cause of settlement is addressed, foam injection can provide a lasting lift, and the cured foam is made to hold up in damp conditions. Longevity depends on the soil and drainage beneath the slab. In active Piedmont clay that keeps swelling and shrinking, or where a downspout is still washing out the subgrade, an unaddressed cause can allow a slab to settle again. That is why we diagnose the cause before we lift the concrete.

One of the advantages of polyurethane foam is that it cures quickly, so in most cases the slab can bear weight again soon after the lift. The exact timing depends on the slab and the conditions, and we will let you know what to expect for your specific project during the inspection.

It can be, because polyurethane foam is much lighter than a cement slurry and adds very little load to ground that may already be loose. That said, foam fills voids and supports the slab; it does not change the deeper soil behavior or drainage conditions that loosened the ground in the first place. In Sandhills sand or saturated coastal soils near Wilmington and Brunswick County, we assess whether foam alone will hold or whether the cause needs correcting too, and we recommend accordingly.

The price for your home depends on the size of the slab, how far it has settled, the number of injection points needed, and access to the area. You receive a written estimate after a free inspection.

See concrete leveling price ranges by service

Not by itself. Foam injection lifts the slab and fills the void beneath it, but it does not change deeper soil behavior or drainage problems that caused the settlement. If the cause is something like water draining against the slab or unstable subgrade, we explain it as part of the recommendation, and where the ground needs deeper support we discuss a structural solution, so the lift is more likely to hold.