Extruded polystyrene (XPS) is an organic insulation material made from styrene. Styrene is extracted from crude oil and inflated into polystyrene with propellants. Extruding creates a versatile insulating material that is characterized by a particularly homogeneous and closed cell structure. This makes it very pressure-resistant and absorbs hardly any water. Extruded polystyrene is ideal as thermal insulation for flat roofs.
Source: bauwion
