Extruded polystyrene is made in the process of polystyrene foaming caused by the addition of a special foaming admixture. The molten mass is squeezed out (extruded) and then rolled to the required thickness. The resulting material has a porous structure with a closed-cell structure and a thin layer of outer epidermis.
Extruded polystyrene boards do not absorb moisture, they are an excellent heat insulator and at the same time they are characterized by high compressive strength. They are slightly heavier than polystyrene boards
Extruded polystyrene is primarily used in places, where thermal insulation is exposed to direct contact with moisture:
o bezpośrednio w styczności z gruntem – floor insulation on the ground, basement walls
o na stropodachach o odwróconym układzie warstw ponad izolacją wodoszczelną.
Extruded polystyrene boards can have various surface preparations. Improving the adhesion of plasters and adhesives is achieved by grinding the surfaces of the elements. There are also used grooved boards or factory-coated with a layer of cement mortar. The edges of the boards can be flat, connected with overlap or tongue and groove.