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Tiling with CM 77 on difficult substrates

The step by step guide how to apply slabs or tiles on difficult substrates with ceresit CM 77 Ultraflex.

Crucial to know

open time 45 min.

temperature 5 to 35°C 

walkable and groutable after 24 h

Tools needed

a water sprinkler

a steel notched trowel

Step 1

Product general info

The product's scope of use

Ceresit CM 77 UltraFlex is a flextec-modified, highly flexible adhesive for the installation of tiles, natural stones and other coverings. It ensures a reliable and firm bond, even on difficult substrates like metal, wood, glass, synthetic resin and coatings – usually without a primer. It can be used on slightly vibrating surfaces in industrial rooms. It is:

  • proper for wall and floor application,
  • proper for indoor and outdoor use,
  • able to absorb stresses.

CM 77 adheres without special pretreatment on metal, wood, concrete, plasters, cement screeds, Xylolite, fibrecement boards, chipboards, existing tile and artificial stone floors and on heated screeds. When applying the adhesive to glass or metal, the substrate surface should be degreased before application.

Step 2

Application of adhesive & tiles

The product's application

Ceresit CM 77 UltraFlex comes ready for use. Do not mix with water. Open the bucket and start work immediately. It can be stored for up to 3 weeks and the adhesive doesn’t dry up if the bucket is closed tightly again. After opening the container, use the adhesive up within 3 weeks. If a skin of dried-up adhesive has formed (e.g. due to improper storage), remove it, but do not stir it in.

  • Please note: CM 77 UltraFlex cures in contact with air moisture. To speed up the curing process simply spray the adhesive layer with water before placing the tiles. Make sure to apply only a spray mist! Do not “flood” the adhesive ridges with water.

When installing large-format slabs (more than 0.2 m2), the adhesive layer should be sprayed with a thin water film to accelerate the curing process.

Tips & Tricks

For professionals

How to tackle cavities under insulation without cutting out large parts of plastered insulation?

The bigger tiles, the larger notches:

  • Tiles up to 30 cm length – notch min. 8 mm
  • Tiles up to 60 cm length – notch min. 10 mm
  • Tiles above 60 cm length – notch 12 mm
  • Large format tiles – notch at least 12 mm.

At larger format and in outside areas please use the buttering floating or floating method. For wall application 65% covering is needed and for outside application min. 95% is needed

products used

  • ${/content/heliux/adhesive/ceresit/com/en/products/tiling/central-pdp#/ceresit-cm-77/SAP_0201SEC013X3/searchResult.productFields.MainImageAltText}
    Ready-to-use tile adhesive with ultra high flexibility for critical substrates, to be used also on slightly vibrating surfaces, suitable for indoors and outdoors. For large tiles. 

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