Obtaining the minimum size of the joint in the tile laying process is possible due to the use of tiles subjected to the rectification process. This does not mean, however, that you can use a completely jointless assembly method.
Rectification is a mechanical process of milling the edge of the tile at right angles. The resulting elements can be laid with no fear of size differences because in the rectification process, each tile obtains the same dimension with an accuracy of 0.2 mm. Both wall and floor tiles are subject to rectification, but in the case of the latter, however, it is particularly important – owing to the rectification of the tiles, the ones intended for mounting on the floors do not have to be grouped on calibres.
The appearance of rectified tiles on the market has caused them to be named jointless – in other words those for assembly which are not required to use any grouts. As the main argument, perfectly equal edges of tiles were given, which when combined with each other give the effect of a uniform ceramic cladding on the whole surface. Unfortunately, this conviction – despite the clear declarations of manufacturers of ceramic claddings – still lingers as right among retail clients, sellers, designers, and some contractors.
In fact, such method of assembly of ceramic tiles carries a huge risk of damaging them, mainly due to the linear expansion of the materials, and more specifically – to the differences between the values of this parameter for the substrate, glue, and ceramic elements mounted on them. To put it simply – each of the layers behaves differently under the influence of external factors and the use of expansion joints and grouts allows to overcome the resulting stresses. Jointless assembly creates a huge risk of damage to already laid tiles and can be treated as a mistake in the construction art.