Schlüter-KERDI-BOARD  Universal substrate panel

More than a construction panel: Our Schlüter-KERDI-BOARD is a true all-round talent. This lightweight, and water impermeable backerboard with a fleece surface can be fastened to the substrate with screws or adhered with tile adhesive. This creates an optimum foundation for tile installation. KERDI-BOARD has official approval as a bonded waterproofing assembly, making it an excellent fit for use in wetrooms. Compared to conventional construction panels, KERDI-BOARD stands out for its low emissions and material composition free of cement and fibreglass.

Further advantages at a glance:

  • Waterproof and temperature-resistant
  • Vapour barrier
  • Thermally insulating
  • Pleasant feel
  • Designed for universal use

What's more, the universal substrate is available in seven different material thicknesses - bound to match your personal project.


Product image KERDI-BOARD 1©Schlüter-Systems KG
Cross-section drawing KERDI-BOARD 1©Schlüter-Systems KG
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Product image KERDI-BOARD 1
Cross-section drawing KERDI-BOARD 1

General product information

What this product does

Schlüter-KERDI-BOARD is a multi-functional tile substrate for wall and floor areas, which can function as a bonded waterproofing assembly together with the tile covering. The versatile panel covers many application areas.

The product is a panel made of extruded rigid foam, which is laminated with a special reinforcement material and a fleece fabric on both sides for effective anchoring in the tile adhesive.

Available in thicknesses of 5, 9, 12.5, 19, 28, 38 and 50 mm, KERDI-BOARD covers a broad range of application areas for creating level, waterproof substrates for tile and stone coverings.

Schlüter-KERDI-BOARD is waterproof and resistant to any chemical stresses that typically occur in conjunction with tiled coverings. Where required, and provided the joints and connection areas are properly installed, KERDI-BOARD can be used in certified bonded waterproofing assemblies.

KERDI-BOARD is suitable for creating tiling substrates on green masonry, existing substrates of any kind, on stud structures made of wood or metal, for creating stand-alone straight or rounded partition walls, for panelling on-wall installations and pipes (pipe boxes), for panelling straight or rounded bathtubs and showers, for creating kitchen countertops, vanities, shelving or any other bathroom structures. It is equally suited for creating level substrates in floor areas when renovating bathrooms with foot traffic and similar spaces.

KERDI-BOARD is easy to cut to size with a utility knife. The product features imprinted gridlines on the top side for quick and neat installation.

Depending on the board thickness, KERDI-BOARD can be fully embedded in wall areas or attached with dabs of adhesive. If necessary, anchors can be used for additional reinforcement. The product is attached to stud structures made of wood or metal using the KERDI-BOARD-ZS fastening screws.

Tiles are then installed directly on KERDI-BOARD, using the thin bed method. Other suitable trowel applied coverings or plaster layers can be utilised, please contact us for advice.

How to install this product

Fully embedded Schlüter-KERDI-BOARD

  1. The adhesive must bond with the substrate and mechanically attach to the KERDI-BOARD anchoring fleece. A dry setting thin-bed tile adhesive according to EN 12004 can be used for most substrates. Otherwise, choose another suitable adhesive and review any potential material incompatibilities beforehand.
  2. Apply thin-set mortar with a notched trowel, either on the substrate or on KERDI-BOARD.
  3. Fully embed Schlüter-KERDI-BOARD in the adhesive, creating a bond with the anchoring fleece. The curing time of the adhesive must be observed.
  4. The individual panels must have abutting joints and be aligned accordingly.
  5. Immediately after adhering KERDI-BOARD, tiles can be installed in the thin-bed method, using a dry-setting thin-bed tile adhesive that meets the requirements of the respective covering. The notch size of the trowel must match the tile format. Observe the curing time of the adhesive.

Schlüter-KERDI-BOARD adhered with spots of mortar

  1. Apply a spot of mortar with a spacing of approx. every 30 cm on Schlüter-KERDI-BOARD. Depending on the thickness of the layer, these spots may consist of cementitious tile adhesive or a suitable bonding mortar.
  2. Set the panels at the wall, press them in place and align them with a spirit level.
  3. Immediately after adhering KERDI-BOARD, tiles can be installed in the thin-bed method, using a dry-setting thin-bed mortar that meets the requirements of the respective covering. The notch size of the trowel must match the tile format. Observe the curing time of the adhesive.

Note: If the installation does not result in a permanent bond between the spots of mortar and the substrate, additional mechanical fastening with the corresponding anchors and screws is required.

Schlüter-KERDI-BOARD on stud structures

  1. Attach Schlüter-KERDI-BOARD either vertically or horizontally on the properly assembled stud structure and fasten it with screws. If using the support plates, the screws can be set into the abutting joint of the panels. Select the length of the screw such that they penetrate wooden stud structures by at least 20 mm and metal stud structures by at least 10 mm. The spacing between screws should not exceed 25 cm. Depending on the on-site requirements, the panel thickness for stud structures (centre line 62.5 cm) should be at least 19 mm.
  2. For vertical placement, install the individual panels with closely abutting joints over the centre of the studs. For horizontal installation, embed all vertical abutting joints that are not supported by a stud with tile adhesive, Schlüter-KERDI-FIX or the double-sided adhesive tape Schlüter-KERDI-BOARD-ZDK. Such abutting joints should be arranged in an offset pattern.

Schlüter-KERDI-BOARD in partition walls

  1. The edge of Schlüter-KERDI-BOARD is adhered at a fixed wall so that the KERDI-BOARD partition wall is integrated into the tile covering installed on the wall. If possible, the partition wall should be incorporated between the KERDI-BOARD panels attached to the fixed wall. As an alternative, a matching angle or U-shaped profile of the system may first be fastened to the fixed wall with screws to integrate the partition wall.
  2. Partition walls with an exposed side can be stabilised with a U-shaped profile included in the system. If fittings are to be attached to the U-shaped profile, the matching flat plastic profile Schlüter-KERDI-BOARD-ZFP should be adhered to the underside of the U-shaped profile to achieve better support for the screws. U-shaped profiles can also be used in floor and ceiling connections.
  3. All vertical and horizontal KERDI-BOARD joints must be sealed with cementitious tile adhesive or KERDI-FIX if applicable. A matching angle or U-shaped profile may be adhered in one or several bed joints to help stabilise longer partition walls.
  4. Depending on the individual construction requirements, such partition walls represent lightweight wall panels without static verification. As a general rule, the panels should have a thickness of 50 mm. Panels used for shelf structures may have a thickness of 19 mm or more. This should be determined based on local requirements at the site.

Schlüter-KERDI-BOARD in floor areas

  1. Schlüter-KERDI-BOARD is suited for creating level substrates in floor areas when renovating sanitary installations with foot traffic and similar spaces.
  2. To accommodate KERDI-BOARD in thicknesses of 5, 9, 12.5 and 19 mm, the substrate must be free of components that may inhibit bonding, sufficiently load bearing and level. Complete any necessary levelling work before installing KERDI-BOARD.
  3. The adhesive must bond with the substrate and mechanically attach to the KERDI-BOARD anchoring fleece. A dry setting thin-bed tile adhesive according to EN 12004 can be used for most substrates. Otherwise, choose another suitable adhesive and review any potential material incompatibilities beforehand.
  4. Apply cementitious tile adhesive on the substrate with a notched trowel and fully embed Schlüter-KERDI-BOARD in the adhesive, creating a bond with the anchoring fleece. The individual panels must have abutting joints and be aligned accordingly. The curing time of the adhesive must be observed.
  5. If the substrate is sufficiently load bearing, KERDI-BOARD from a thickness of 28 mm can also be installed and aligned over spots of thin-bed mortar or another mortar types. The spots of mortar must be adequately spaced to ensure proper load bearing. Apply thin-bed mortar over the joints at the panel edges and make sure that joints are located over the spots of mortar.
  6. Prevent the build-up of tension at KERDI-BOARD or the tile covering in the edge areas, for example by installing an edge strip.
  7. Immediately after fully embedding KERDI-BOARD, the tiles (minimum size 5 x 5 cm) can be installed in the thin-bed method, using a thin-bed tile adhesive that meets the requirements of the respective covering. If using spots of mortar, make sure to allow for sufficient curing until they are properly load-bearing. The notch size of the trowel must match the tile format. Observe the curing time of the adhesive.
  8. Follow the instructions of the relevant technical regulations to install movement joints for perimeter, edge and connection joints.

Waterproofing with Schlüter-KERDI-BOARD

Schlüter-KERDI-BOARD can be installed in accordance with the waterproofing standard DIN 18534 applicable in Germany. Water exposure classes: W0-I to W3-I*. In addition, Schlüter-KERDI-BOARD features the national technical approval (abP) required in Germany.

Moisture load class according to ZDB: 0 to B0, as well as A and C.

KERDI-BOARD features European Technical Approval (ETA) pursuant to ETAG 022 (watertight covering kits) and bears a CE mark. System-certified tile adhesives must be used in areas that require CE-compliance or assemblies according to abP (certificate of technical approval).

* With abP and/or based on ETA according to ETAG 022. Our Technical Department will be pleased to provide information on use and installation on request.

We recommend the use of our waterproofing membrane Schlüter-KERDI (see product data sheet 8.1 Schlüter-KERDI) for load class B "containers", (e.g. for swimming pools).

Cover the abutting joints in the surface and in the corner areas of KERDI-BOARD by fully embedding the sealing band Schlüter-KERDI-KEBA in a minimum width of 12.5 cm in the sealing adhesive Schlüter-KERDI-COLL-L. The sealing band must have a coverage of at least 5 cm.

KERDI-KEBA can also be used to create functional connections to fixed structural components such as door and window frames made of metal, wood or plastic. To this end, apply KERDI-FIX on the bonding surface of structural components and KERDI-COLL-L on the bonding surface of KERDI-BOARD and fully cover the entire joint area with sealing band.

The suitability of KERDI-FIX for the respective material of the structural elements must be verified in advance. The feasibility of connections must be assessed based on the conditions of the construction site. Seal all connections with proper care.

Separate KERDI-BOARD at existing movement joints or expansion joints and seal the abutting joints with Schlüter-KERDI-FLEX. KERDI-FLEX should also be used for flexible finishing edges.

Rendered and plaster surfaces on Schlüter-KERDI-BOARD

KERDI-BOARD is a suitable substrate for rendered and plaster surfaces as well. These can be surfaces adjoining tiled areas (e.g. half-height walls) or entire walls in other areas.

The abutting joints in the surface and at external and internal corners must be reinforced, along with exposed edges, to be covered with trowel-applied mortar. Our self-adhesive joint reinforcement KERDI-BOARD-ZSA may be used for this purpose.

What this product is made from

Schlüter-KERDI-BOARD is made of an extruded XPS rigid foam with a cement-free reinforcement layer and an anchoring fleece laminated on both sides. The upper face of the board is imprinted with 10 x 10 mm square gridlines.

Material properties and areas of application

Schlüter-KERDI-BOARD is waterproof and resistant to any chemical stresses that typically occur in conjunction with tiled coverings. Where required, a certified bonded waterproofing assembly can be created with KERDI-BOARD.

KERDI-BOARD is completely level and remains free of distortions and decay. It will not rot and is highly stable, even with one side exposed to temperature fluctuations and moisture.

KERDI-BOARD is ideal for a wide variety of applications. Product suitability must be verified in applications exposed to chemical or mechanical stresses. The information provided below is intended as a general guideline.

Substrates on which KERDI-BOARD is to be installed must be checked for sufficient stability and other project-related requirements. If directly adhering the product, remove all surface components that may weaken the bond. Alternatively, the product can be fastened mechanically with the corresponding anchors or screws.

Select a sufficient material thickness for building free-standing partition walls, shelves etc. out of KERDI-BOARD. Reinforcement profiles may be needed.

In floor areas, the use of KERDI-BOARD is restricted to areas with foot traffic. Depending on the system, stepping on such coverings with hard shoes or tapping them with a hard object may produce a hollow sound.

Select the material thickness and installation method according to the levelness of the substrate. Thin panels of KERDI-BOARD (5 mm) must be fully embedded in the adhesive.

How to look after this product

Store KERDI-BOARD on a flat surface or in another suitable form. When stored outside, the product must be protected against direct sun exposure and weather.

Bathroom features such as vanities, toilets or other heavy objects installed with the product must be anchored in the weight-bearing substrate. In case of substrates comprising stud structures or on-wall installation, attachment to the weight-bearing elements is mandatory. In addition, an abutment must be installed at the bottom of such structures, which may need to be reinforced.

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