Covering material for foamed polystyrene form unit - comprises layered low friction water, repellent plastic layers with crosspiece links

摘要

The covering material prevents soft concrete from clinging to the form units, so that they can be used again. This involves use of plastics, in double or multiple layering, with water-repellant qualities and with lowest possible friction relative to foamed polystyrene. Its successive layers are interconnected and held at a small interval apart by stiffening cross arm stems. The interval between these may correspond to the interval between the layers; or the cross arm stems may be arranged in honeycomb form. The individual plastic layers may be formed out of mutually weldable material. This permits easy removal of form units when concrete has set hard.