Features and Benefits

White, flexible tile adhesive for outdoor installation of thin natural stones and glass & fine mosaic


  • High instant tack
  • Faster hardening, flexible consistency
  • White & very fine-grained structure
  • Easily workable
  • Rapidly ready for grouting
  • For use on underfloor heating
  • For balconies, terraces and facades

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Thanks to its white colour and working properties, CM 25 is especially recommended for laying glass mosaics or tiles where a uniform substrate colour is wanted - but also for the discoloration-proof fixing of bright and translucent marble and other natural stone slabs, using the thin-bed method. CM 25 is well suited for application of different kind of tiles (ceramics, fine stoneware, natural stone) and agglomerate slabs on critical substrates.

Step by step

Substrate preparation

CM 25 adheres to all clean, solid, load-bearing, even, dry and moist substrates, which are free from substances which can reduce adhesion. Uneven areas or depressions should be levelled before (see Ceresit Flooring and Interior Finishes products). Coatings of insufficient load-bearing strength must be removed. Gypsum/anhydrite or paint coats (not chalking, good adhesion) must be mechanically roughened and freed from dust.
Before applying CM 25 tile adhesive, check the residual moisture of the substrate! Absorbent substrates should be primed with Ceresit primer.
Please refer to the Technical Data sheet!


Pour the content of the packaging into the measured amount of clean, cool water and mixe it with a drill mixer until a homogenous mass without lumps is obtained. It is necessary to wait for 5 minutes (maturing time) and then mix it once again. If necessary, carefully add water until the desired consistency is achieved.


The adhesive should be applied with a suitable notched trowel, depending on the respective tile size. For indoor use, the mortar coverage (contact area) at the back of the tile must be at least 65 %. For outdoor use, a minimum mortar coverage of 90 % is required (combined laying method  should be used i.e. additionally apply a thin layer of the mortar on the tile backside). CM 25 is fast setting - keep in mind the shortened skin formation time and pot life compared to normal setting tile adhesive.
Fresh excess mortar can be removed with water; hardened material can only mechanically be removed.
Use CM 25 only in dry conditions and at temperatures of +5 °C to +30 °C.