Strong Bond

Mapei presents Keraflex Maxi S1, an adhesive for installation of large format tiles.

Over the last few years, manufacturers of ceramic tiles have extended their range of large format tiles. Apart from the 3 and 5 mm thick 3 m x 1 m formats, they are now proposing formats that can reach sizes of up to 1.6 m x 3.2 m and thicknesses ranging from 5 mm up to 12 mm.

Mapei has always worked closely with leading manufacturers of large format tiles and has also progressed in line with these new products by developing and producing new products suitable for installing these types of material. The particularly large format and extremely low absorption rate, typical characteristics of porcelain, means that it is important to identify the most suitable installation method for this type of tile with extreme care and precision. As with any floor and wall dressing, the durability and functionality of slim porcelain is also highly dependent on precise design parameters, appropriate substrate preparation and correct installation methods using adhesives, grouting mortars and joint sealants which have been chosen according to the type of dressing material and its area of use.

Choosing the right adhesive is fundamental to ensure a durable, sound bond over the years and depends on the type of substrate, the type and format (dimensions and thickness) of the tiles, the area of use and the surrounding conditions. If we bear in mind the prescriptions of current standards, when installing this type of material, it is recommended to use high adhesion cementitious adhesives, that is, class C2 according to EN 12004. For certain types of substrates, it is more appropriate to use reactive adhesive, or class R2 according to EN 12004.

Standards always prescribe the use of deformable adhesives, class S1 or S2 according to EN 12004. 

For medium sized formats class S1 adhesives are recommended, while for large formats it is strongly recommended to use highly deformable class S2 products. 

The deformability of adhesive is determined through flexural tests (the method described in EN 12004 - ISO 13307) which measures transversal deformation. To achieve class S1, the deformability of the sample must be at least 2.5 mm and for class S2 it must be at least 5 mm.

Mapei Products that are used for installation of large format tiles after the substrate preparation are:

Levelling Mortar before tile installation – Ultraplan Eco 20.Tile installation: 

- Adhesive – Keraflex Maxi S1

- Filling the Joints – Keracolor SF / Ultracolor Plus

- Epoxy Grout – Kerapoxy / Kerapoxy Design.