Superior Walls’ XiPlus foundation panels have an insulation value of R-21 (compared with R-12.5 for the maker’s standard Xi panels), thanks to 4 inches of extruded polystyrene insulation and 2 1/2 inches of Dow Thermax. All Superior Walls have a 2 1/2-inch-thick polypropylene-reinforced concrete shell, along with 8-inch-thick steel-reinforced concrete studs and footer and header beams. Everything is monolithically poured with 5,000-psi concrete. The studs have galvanized metal facings for fastening drywall. All panels are custom-fabricated, with costs ranging from $60 to $80 per linear foot. Current availability is in the Eastern U.S.
Superior Walls, 800/452-9255, superiorwalls.com.