The 2" polystyrene which constitutes permanent insulation formwork, comes in planks 8 ft. By 8 in., slotted every 8 in. on the long sides to take the tie rods. These hold the polystyrene planks together, act as spacers between the two polystyrene walls to insure the alignment of the vertical in-wall bracing. (Bracing is required in walls 4 ft. or more in height. It replaces conventional exterior 2x4 form bracing-which is an acceptable alternative.)

Tie rods are available in several lengths for different concrete wall thicknesses: 4" to 12" and 16" to 24" in 2" increments. In-wall bracing is available and sized to fit the appropriate wall thickness.

Special tie rods accommodate corners and wall junctions. Relatively simple techniques permit corbelling, pilasters curved walls, etc.