Not every shower floor installation starts at the same height as the surrounding bathroom floor — and that height difference has to go somewhere. The KERDI-SHOWER Compensation Board (KERDI-SHOWER-CB) is a lightweight expanded polystyrene (EPS) board designed to make up the difference when your KERDI-SHOWER tray sits lower than adjacent flooring, or to provide a smooth transition between assemblies at different heights.

Available in two thicknesses to address different height differentials, the compensation board is easy to cut with a utility knife and integrates into the KERDI shower system without adhesives — just set in mortar like the tray itself.

When you need it

• The KERDI-SHOWER-T tray sets below bathroom floor level and a filler is needed at the perimeter
• Creating a gradual transition between the shower floor and bathroom tile at different finished heights
• Leveling out substrate irregularities at the perimeter of the shower tray before tiling
• Adding height to sections of the assembly to match existing flooring elevation

Key features

• Lightweight EPS foam — same material as the shower trays themselves
• Can be trimmed to any shape with a utility knife
• Fully compatible with KERDI waterproofing system
• Sets in thin-set mortar, tile directly over it after KERDI membrane application

What it pairs with

• KERDI-SHOWER-T, TT, LT, and LTS shower trays
• KERDI-SHOWER-R ramp (for sloped entry transitions in curbless designs)
• KERDI-BAND to seal the compensation board perimeter joint into the waterproofing envelope

Pro Tips

• Measure the height differential before ordering — the two available thicknesses cover different gaps. Combining boards is acceptable for larger differences
• Always include the compensation board area in your KERDI membrane waterproofing — it's part of the shower assembly and must be within the waterproof envelope
• Bond with the same thin-set as the tray (Schluter SET for concrete, ALL-SET for wood subfloors)
• If you're building a curbless shower and using a KERDI-SHOWER-TT (thin tray), the CB boards often aren't needed — the TT tray's reduced perimeter height is specifically designed to minimize this problem