The contactor used AP Fill 420 to fill the void. 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.
The contractor filled the entire void with AP Fill 420 foam. This material was faster to install, less expensive, and provided a more waterproof solution than the foam blocks.
The entire void was filled with lightweight and extremely durable polyurethane foam. This material placed minimal pressure on the retaining wall, eliminating the danger of future damage. The property owner was extremely pleased with the results.