External wall cladding - of polystyrene keyed squares covered with plastic cement with lower expansion coefficient

摘要

The polystyrene squares are fitted at the sides with mating hooks, and are fitted with grooves for mortaring to the wall on one side, and for keying the plastic cement layer on the other. The different expansions of the polystyrene and the plastic cement ensure that the outer surface is held under controlled tension, and this is transmitted through the grooves of the polystyrene to ensure that the outer surface does not crack in use.