Interlocking blocks of expanded polystyrene (EPS) have been used as permanent forms for a variety of wall installations, with concrete being placed in the voids in the patented EPS blocks. The standard form blocks are each 10x10x40 inches and have interlocking notched edges that make it simple to lay and align the blocks into a tightly fitted wall surface. For more economical construction of landscaping and noise barrier walls the manufacturer has introduced another block, 8x10x40 inches. Other interlocking EPS wall forms suitable for residential and commercial construction are available with plastic cross ties instead of the molded bridges.

Generally the EPS-formed barrier walls are supported on intermittent piers instead of the solid spread footing required for some other types of wall construction. Corners and intersecting walls create added strength for the form assembly, since the system is designed to interlock at right angles as well as longitudinally. Special end caps installed at the corners prevent leakage of concrete and maintain continuity of the EPS. Where a curved wall is desired, vertical slits are cut in the walls of the form blocks on the inside of the curve and the forms are bent until the gaps close, then braced into place.