A new idea in composite walls with insulation values reportedly attainable up to R-19 is being used to build homes and other structures at considerable savings. The heart of the system is a manufactured panel core consisting of expanded polystyrene board and a wire cage on which Portland cement plaster can be applied to both sides. Plastering techniques can include hand plastering, standard gun plastering and wet or dry shotcreting. Walls can be given any of a variety of surface finishes. The 4- by 8-foot panel that forms the core of the wall to which Portland cement plaster is applied is made up of a 2 1/4-inch-thick board of expanded polystyrene enclosed between two wire grids. The grids are spaced far enough away from the polystyrene to permit later encasement in plaster. Continuous wire trusses running through the polystyrene tie the two grids into a tough wire cage; hence, the two plaster layers become the outside wythes of an insulated sandwich panel.
The wire-and-plastic-foam panels are manufactured in a central plant and trucked to the site where a floor slab has previously been placed and finished. Since the panels individually weigh only 26 pounds they can be readily handled by one person. Panels are set into sheet metal screeds anchored to the perimeter of the floor slab. Adjoining panels are attached to one another by means of metal clips that clamp overlapping joint mesh duplicating the mesh of the panel. The walls are plumbed and braced into position.
This system offers cost savings to builders in a shortened erection time, which results in lower financing costs, and in lower labor costs as a result of heavy use of semiskilled labor, eliminating carpentry, plumbing and other trades. Engineering studies show that the system offers excellent passive solar energy characteristics, which in the southern California market can reduce homeowner heating costs by more than 50 percent and reduce cooling costs by 70 percent.