Large format ceramic and porcelain tiles cover a larger area, require fewer gaps and breaks (grout lines and expansion joints, which are often overlooked) and create the illusion of a monolithic, seamless finish. For many people, this is considered to be an advantage and is highly appreciated by architects and clients. As technicians, we should be asking ourselves: do we use the same installation system for large format tiles as the one’s used for small to medium size tiles – the answer is No! Are there any particular precautions we need to take – the answer is Yes!
What does “large format tile” actually mean?
Large format tiles are defined as those having one side longer than 60 cm. For the purposes of this article, we will consider tile formats of up to 3 m, and which in certain cases may even exceed these limits, with a thickness of 3 to 6 mm.
What are the most important factors when installing large format tiles?
1). Movement and Handling:
Particularly large tiles are usually handled and moved around on site using suction cups and rigid frames.
These all help to stop tiles bending too much, which could lead to them cracking or even breaking.
Handling large tiles also requires a proper number of operators.
The substrate to which large format tiles are bonded, particularly when using thinner tiles, must be
perfectly flat. The requirement is applicable for the installation of floor and wall tiles in general, but it
becomes even more critical when installing large format and slim ceramic/porcelain tiles or stone slabs.
If the installation surface is too uneven, it could cause the tiles to crack.
What type of adhesive should be used to install large format tiles?
The adhesive should be of the improved adhesion type and, in most cases (if not all), it should also be deformable. Why? The larger the surface area of the tile, the higher the stress and amount of work the installation surface/adhesive/tile system will be subjected to. Natural deformations, or those induced by external events (such as temperature variations), could detach or damage the covering.
Improved adhesion (class 2) and deformable (class S1) adhesive systems are recommended for tiles with one side measuring more than 90cm or 120cm. Deformable adhesives are characterised by their lower modulus of elasticity which makes them more efficient at “cushioning” strains.
Mapei’s Kerabond T-R is a cementitious tile adhesive of class C1. Mixing it with Isolastic in place of water improves its characteristics to meet the requirements of class C2E S2 (improved, highly deformable, cementitious adhesive with expended open time).
Besides the adhesive, grout lines, expansion joints and double-buttering are all fundamental aspects that need to be considered in order to install large format tiles successfully.
For more information and technical insight on your large format tiling project, please contact Mapei South Africa’s technical department.