One of the most resilient void fill foams, AP Fill 420 is a two-component, high expansion, hydro insensitive polyurethane foam. It’s the top slab solution for polyurethane void fill. AP Fill 420 weighs 1.8 to 2.2 pounds per cubic foot. For similar products, see the page on Concrete Leveling.
Two component proportioner with material heaters.
MixMaster Pro slab lifting gun.