Several wall forming systems now on the market and particularly well suited to home construction make concrete the meat in a sandwich of insulation. Easily assembled lightweight forms of expanded polystyrene (EPS), usually 2 inches thick, stay in place after concrete is poured, providing a wall with an R value of about 20 before any finish materials are applied.
HOW THE WALLS ARE BUILT
A starter plate of wood on the foundation slab or footing helps align the first course of formwork. Depending on the particular system used, ties are either installed as the courses are assembled or are already integrated into the forming units so that fitting the interlocking blocks together is all that is required. Any necessary reinforcing steel can be placed as the forms are being assembled. The EPS forms require external bracing and accurate alignment just as all other wall forms do.