It’s very important to adhere to the British Standard when fixing large format thin porcelain tiles and panels, as they are fragile and easy to damage during handling and they can crack if they are not laid correctly leading to failure of the installation. Handle the tiles using suitable lifting equipment taking special care with corners and edges.
For floors, the substrate should be totally level and stable. Laying on top of an existing sound tile installation is ideal, otherwise the use of a rapid hardening self-levelling compound such as Levelflex Gel or Proflow MVS is recommended. Adequate time should be left to ensure that all substrates are properly cured to avoid movement after tile installation.
Care should be taken when fixing to ensure that there are no air cavities under the tiles and that the back of the tile is entirely covered by adhesive. The standard recommends the use of both back buttering the tile and a layer of adhesive spread across the floor, spreading only enough adhesive for one tile at a time to avoid a skin forming on the adhesive as this could prevent proper adhesion. H40 gel-adhesives are suitable for this sort of installation, as they thoroughly wet the back of the tile, do not shrink and hold their shape meaning that the tile is fully supported. H40 Gel has an open time of up to 60 minutes at 23°C making “skinning” before the tile is laid extremely unlikely.
Grout joints should be at least 5mm for 3m long tiles to allow adequate room for potential movement and avoid damaging fragile edges and corners. Movement joints should also be built in to allow for shrinkage of, or movement in the substrate. Under no circumstances should the tiles be butt-jointed. Kerakoll recommends the use of Fugabella Color grout which can be used on joints from 2–12mm, and is said to be extremely durable, waterproof and colourfast with low Volatile Organic Compounds (GEV-Emicode 1). All joints should be clear of adhesive as far as possible to avoid cracking of the grout where there is not adequate depth of coverage.
Movement joints should be filled with Silicone Color which is available in the same colour range as Fugabella Color.
The same principles apply for thin wall tiles. It is imperative that the substrate is totally solid and not flexible. Tiling onto plywood is in any case outlawed by the British Standards and a suitable tile backer board should be used instead. It is advisable to use a flexible adhesive – the Setaflex range is suitable, or any of the H40 gel-adhesives can be used to fix the tiles.
01772 456831
info@kerakoll.co.uk
www.kerakoll.com
