Features and Benefits

White tile adhesive with Trass for most natural stones


  • White tile adhesive, especially for natural and artificial stone
  • Minimizes risk of efflorescence and discoloration
  • No showing-through of the bedding mortar
  • Based on trass and white cement
  • High flexibility and adhesion
  • For layers up to 10 mm thickness

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CERESIT® CM 42 is a white cementitious thin-bed/medium-bed adhesive mortar with trass additive, ideal for laying wall and floor coverings made of natural or artificial stone, marble and mosaic but also ceramic tiles and slabs indoors and outdoors. Flexible adhesive bed to avoid shear stress on critical substrates. Suitable for repairs before installing tiles and for levelling unevenness of up to 10 mm.


Available pack size: 25kg

Step by step

Substrate preparation

CERESIT CM 42 adheres to all solid, load-bearing, clean and dry substrates free of substances that may impair adhesion. Coatings of insufficient load-bearing strength must be removed. For levelling and raising the level of cementitious floors we recommend using CERESIT CN 39 or CERESIT CN 72. Highly absorbent substrates must be primed with CERESIT CT 17. When installing tiles on existing ceramic or natural stone coverings, we recommend a full-surface coat of CERESIT CT 19.


Mix CERESIT CM 42 with the predefined amount of clean water (see Technical Data) until the mixture is smooth and free of lumps. Leave to mature for approx. 5 minutes, then give the mortar a final stir.


Use a trowel with a suitable notch size. Natural/artificial stone slabs or ceramic tiles must be installed within the open time of the mortar (see Technical Data); otherwise, the required effort will be too high. For large tiles/slabs and outdoor areas we recommend using the floating-buttering method. Fresh mortar stains can be removed with water; hardened residues can only be removed mechanically.