How to install large format and slim tiles
Flat and sound substrate
The installation substrate must be as levelled and flat as possible. To install large-size tiles, the flatness and accuracy of the substrate must be within 1.5mm with a 2m straight-edge. Any areas not within this tolerance must be repaired before commencing installation. In addition, the substrate must be sound with no cracks, cured and dimensionally stable and clean.
Choosing the right tile adhesive
As the size of the tiles increase, the risk of the tile not fully in contact and covered with the adhesive bed may be higher and therefore the use of adhesives with high wetting capability is ideal. In this way, gaps are not created that could otherwise affect the soundness and durability of the bond.
In addition, improved adhesives under class C2 with deformable properties of Class S1 or S2 in accordance with EN 12004 & ISO 13007-1 are recommended for installing this type of tiles. Refer to our article on Understanding Tile Adhesives and their Standards for more information. The deformability of the adhesive is determined through flexural tests which measures transverse deformation. To achieve Class S1, deformability of the sample must be at least 2.5 mm and for Class S2, it must be at least 5 mm. Ultimately, the type of adhesive depends on the type of substrate material, type and size of the tiles and the area of use.
Measuring the deformabillity of cementitious adhesive
Double-trowelling & buttering technique during tile installation
Tile adhesive is spread in the same direction on the back of the tile and on the substrate
Tiles must be installed on a compact bed of adhesive. It is recommended to use the double-buttering technique when applying the adhesive. Likewise, for thin porcelain slabs, this technique is recommended as gaps may form potential weak points in the tiling that could easily fracture.
Double-buttering technique, that is, applying the adhesive with a steel notched trowel on both the substrate and on the back of the tile, must be used. The adhesive should be spread on the substrate and back of tile in the same direction. The adhesive must be applied in straight lines parallel to the short side of the tile to reduce the distance travelled by the air being pushed out. This will ensure that gaps are not created that could otherwise affect the soundness and durability of the bond.
How to spread tile adhesive correctly on large tiles
The sheer size of the tiles may lead to the formation of air pockets between the substrate and the back of the tile. This is why it is important to go over the tile surface by tapping them with a rubber spreader or vibro-plate, particularly when installing tiles on external substrates where water may collect in the gaps.
Tapping the tile by hand or going over the surface with a vibro-plate