XPS is extruded and EPS is expanded. Extrusion produces a finer, fully closed cell structure, so XPS absorbs virtually no water and takes much higher compressive loads. EPS is lighter and cheaper, but XPS is specified where moisture and load are present: inverted roofs, floors under screed, perimeters and below-ground walls.

Yes. XPS is the standard choice above the waterproofing membrane, because the closed-cell structure means it keeps its thermal performance even when saturated. Our boards are covered by ATG 2975 and CTG-493 for inverted roof applications.

Styrisol® boards run from 20 to 160 mm. The 140 and 160 mm thicknesses are produced on request, subject to a minimum order quantity. Declared thermal resistance ranges from Rd 0.55 at 20 mm to Rd 4.55 at 160 mm.

Declared thermal resistance depends on thickness: Rd 1.40 at 50 mm, Rd 2.85 at 100 mm and Rd 4.55 at 160 mm for smooth and waffled boards. Full declared values per thickness are listed in the specifications table above and in the technical data sheets.

Virtually none. The closed-cell structure prevents water being absorbed into the board, which is why XPS keeps its declared thermal performance in damp conditions: below ground, under screeds and above the membrane on an inverted roof.

Straight edges suit butt-jointed and multi-layer build-ups. L-cut boards overlap at the joint, reducing thermal bridging. Tongue and groove creates an interlocking joint, commonly used for floors and continuous insulation layers.

Extruded polystyrene is compatible with most building materials, including lime, cement, plaster, alcohols, acids and bases. Petroleum-based solvents, coal tar and derivatives can attack the material, as can thinners such as acetone, ethyl acetate, petrol and toluene. Use solvent-free adhesives and verify compatibility before application.

Yes. Styrisol® boards are 100% recyclable. Our production reuses internal XPS residual waste and converts EPS waste into XPS raw material, and our recycled content is certified by Centexbel. The GR-300 and GR-500 grades are covered by an Environmental Product Declaration.

Styrisol® holds ATG and CTG approvals in Belgium, ACERMI certification in France, Keymark and DIN CERTCO in Germany, and SIA 279 in Switzerland. All certificates are available in the Document Center, filtered by product family and language.

Both are Styrisol® extruded polystyrene. Building boards are supplied in construction formats from 20 to 160 mm with the certifications required for insulating roofs, floors, walls and cellars. Industrial boards are cut to a manufacturer’s specification as a core material inside their own products.