XPS Tile Backer Boards

Coated XPS tile backer boards from 4 mm to 50 mm for shower walls, wet-room floors and project-specific tiling assemblies. Each board combines a closed-cell XPS core with alkali-resistant fiberglass mesh and a polymer-modified cementitious coating. Factory data reports 0.8% water absorption after 96 hours of immersion. Applicable boards carry CE marking to EN 13164; ICC-ES PMG-1804 applies to the evaluated tileable shower system. Choose thickness by the substrate, framing and tile assembly—not by how wet the room is. Custom sizes and thicknesses can be reviewed against your drawing.

  • Choose board thickness by substrate and framing

    Thickness changes stiffness and insulation; it does not replace correct framing, fixing or joint sealing. Use these starting points, then confirm the complete assembly for your project.

    • 6 mm: for installation over continuous solid backing such as wood or OSB, not for spanning open studs.
    • 10–12 mm: a common range for shower walls on suitable framing and for wet-room floors over a concrete slab. Check the framing spacing, tile weight and specified fixing pattern.
    • 20 mm: for approved wider-stud, uneven-substrate and pipe-boxing assemblies. See our 20 mm XPS backer board for the dedicated product option.
    • 30–50 mm: for insulation-led applications, benches and other fabricated elements where the assembly design allows them.

    For the wall-by-wall selection logic, read our XPS backer board thickness guide.

    Check the board data and certification scope

    Our standard XPS core is produced in-house at a nominal density of 35 kg/m³. Factory data reports 0.8% water absorption after 96 hours of immersion, 361 kPa compressive strength at 10% deformation, 0.030 W/(m·K) thermal conductivity at 25 °C and a 1,842 N bending load for a 12 mm board. These figures belong to their stated samples and test conditions; they are not interchangeable across every thickness or application.

    Applicable boards carry CE marking to EN 13164:2012+A1:2015. ICC-ES PMG-1804 applies to the evaluated tileable shower system, not as blanket approval for every individual board or wall assembly. Applicable certificates, test reports and installation documents are available through our Resources and downloads page.

    Frequently asked questions

    Should I choose 6 mm, 12 mm or 20 mm?

    Start with the support behind the board. Use 6 mm over continuous solid backing, consider 12 mm for suitable standard shower-wall framing, and review 20 mm where the approved assembly calls for additional stiffness or build-out. Send the substrate, stud spacing and tile format before ordering if the wall does not match a standard detail.

    Is 12 mm the same as 12.7 mm?

    No. They are different nominal thicknesses. The IAPMO PS 106 report identifies 12.7 mm for the tested vertical polystyrene components without solid backing and 6.35 mm for the specified solid-backed assemblies. Do not automatically substitute a 12 mm board where a project specifies 12.7 mm; confirm the current evaluated system, substrate, framing and local requirements.

    If the board is waterproof, why do the joints still need sealing?

    The closed-cell board resists water, but a tiled shower includes joints, corners, fasteners, penetrations and a tray or drain connection. Those details must be sealed with the specified system components. A waterproof panel alone does not make the complete shower waterproof.

    Tell us the substrate, stud spacing, board size, thickness and quantity through our project contact form. We will confirm the appropriate board and compatible fixing and sealing components for your project.