The same material that many contractors use to insulate walls and roofs—expanded polystyrene (EPS)—can help reduce lateral loads on building foundations and retaining walls. EPS geofoam is a lightweight fill that allows for the use of thinner walls, with less material, as well as a reduction in labor needed for concrete forming or the installation of segmented retaining wall blocks.
EPS geofoam has the same composition as EPS insulation, but is formed into blocks, rather than sheets. As a fill material, a key advantage of EPS is its ultra low weight—approximately 100 times lighter than soil (one to three pounds per cubic foot compared to 110 to 120 pounds for soil). EPS geofoam enables contractors to backfill against walls and foundations, replacing the heavy soil wedge customary with traditional fill materials.