Improved manufacturing techniques allow for the production of porcelain and ceramic tiles in larger formats. With increased use of these by both commercial and residential tiling markets, the specialised requirements for successfully fixing these large-format tiles are key.
Large-format tiles may have permissible manufacturing tolerances or surface flatness irregularities, i.e., the tile surface may be “curved” or “bowed”. It is therefore vital that the substrate to be tiled is smooth and level by applying a self-levelling underlayment. This also prevents the excessive consumption of tile adhesive.
The laying of tiles in a brick/running bond pattern should be carefully considered because of potential lipping caused by the curvature of large-format tiles. A maximum offset of 30% is recommended.
Top tips for installing large-format tiles.
The use of self-levelling spacer or clip systems will further assist with reducing “lippage”.
A specialised tile adhesive, designed with a longer open time, is required when fixing large tiles. This extra time allows for the “double-trowelling” technique, where adhesive is applied on both the substrate and the back of the tiles, using suitable trowels, to ensure full contact and a solid bed of adhesive behind each tile.
It is imperative that the installation process is seamless to prevent the adhesive on the substrate or back of tile from “skinning”, and an impaired bond. A “wet to wet” adhesive bond is essential.
Tile and movement joints
The grout joint width for fixing large-format porcelain tiles (including rectified tiles) should be no less than 3mm wide, and no less than 5mm wide for ceramic tiles.
When installing large-format tiles, there is a smaller number of joints between the tiles, as compared with the same area of normal format tiling. Less stress (movement) can therefore be accommodated at the tile joints, and allowances must be made for this. Modifying the grout with a latex additive will allow for more flexibility and bond strength within the installation.
Tile panel movement joints and perimeter joints must be a minimum of 5mm wide, most be located at the required centres, and must be correctly constructed.
Tips and tools
- Handle large tiles carefully, avoiding breaks or chips.
- Employ teams to manage these physically demanding installations.
- When transporting extra-large tiles on site, a wheeled cart or dolly minimises physical strain and accidental drops.
- Easily lift and carry large tiles with suction cup holders to the risk of damage.
A large-format tile is defined as having one edge with a length greater than 600mm, or a facial area greater than 3 500cm², i.e., 600x600mm or larger in size.
For more information, contact TAL:
Tel: +27 860 000 TAL (825)