What is considered as Large format and slim tile?
Large-format tiles are those with at least one side greater than 60cm in length. They come in various sizes and thicknesses, with some formats reaching dimensions of up to 3.2m x 1.6m. They are usually made from porcelain and, as such, have a low rate of absorbency. Slim tiles are around 3-5mm thick in formats up to 1m x 3m. They may be reinforced with glass fibre mesh backing.
Large-size tiles allow an almost seamless surface. Handling and moving large format tiles require more people and the use of tools with special suckers. Particular care must be taken when handling these tiles to avoid warpage and chipping the corners.
An advantage of thin tiles is the lower weight of this type of tile compared to traditional tiles, which means less impact on the structure, a characteristic that makes it the preferred choice for installing on vertical surfaces, especially facades. However, their reduced thickness means that certain precautions need to be taken during handling when preparing substrates and bonding tiles.
Let’s take a look at some points to look out for to ensure successful installation of large format and slim tiles.
How to install large format and slim tiles
The installation substrate must be as leveled 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.
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 underclass C2 with deformable properties of Class S1 or S2 in accordance to 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 that measure transverse 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. Ultimately, the type of adhesive depends on the type of substrate material, type and size of the tiles, and the area of use.
Tiles must be installed on a compact bed of tile 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.
The double-buttering technique, that is, applying the Tile 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 the tile in the same direction. The Tile adhesive must be applied in straight lines parallel to the short side of the tile to reduce the distance traveled by air being pushed out. This will ensure that gaps are not created that could otherwise affect the soundness and durability of the bond.
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.
The grout line between each tile must be at least 2 mm wide and must be increased according to the size and type of the tiles, the area of use (floor or wall tiles, internal or external), and the stresses expected when in service. It is recommended to use spacers between the tiles to ensure the correct gap between each tile.
Keep in touch
Subscribe to our newsletter to get Mapei news
