The wedi building board consists of an extruded rigid polystyrene foam core with fibre glass reinforcement on both sides and a cement mortar coating.

Extruded rigid polystyrene foam (XPS) is a plastic foam insulation material which complies with /EN 13164/, which is produced in the form of boards within the bulk density range of 35 kg/m³ (+/-3).

The wedi building board including the coating has an arithmetical density of 177 kg/m³. wedi building boards are supplied in thicknesses from 4 mm to 100 mm and with trimmed edges.