Ceramic tiles: selection criteria

Before presenting the main topic of the article, it is necessary to emphasize the importance of the existence of standards in general. The advantage of having standards is that they provide the opportunity to accurately determine the criteria for the most successful selection of tiles.

Water absorption

For example, consider two parameters on the basis of which tiles are classified. The first, water absorption, measures porosity. A high degree of water absorption means that the structure is porous, and a low degree (the value tends to zero) indicates the density of the structure. As a rule, the lowest water absorption values ​​(groups AI and BI, see EN 14411 standard) correspond to higher tile characteristics such as: mechanical strength, hardness, resistance to abrasion and chemical influences (implies unglazed tiles), frost resistance. It is obvious that tiles from the AI ​​and BI groups should be used for covering surfaces exposed to strong chemicals (for example, public places such as offices, supermarkets, shopping centers, cafes, etc. or industrial premises such as laboratories, workshops, etc. ) and hydrothermal effects (external surfaces, refrigeration chambers). As a result, the requirements for AI and BI groups are much higher than the requirements for other groups. At the same time, it is necessary to remember that the structural density is obtained through the use of appropriate raw materials and high firing temperatures, with the formation of a significant part of the liquid phase in the tile mass. This requires more careful control over the dimensional characteristics, since there is a risk of varying not only the flatness of the surface, but also the working size of the tile. This does not pose a threat to porous tiles.

Extrusion or pressing

The molding method is another parameter of the EN 14411 standard that affects the geometric configuration of the tiles. As a rule, it is impossible to achieve such careful control over the surface and dimensions with the extrusion method as with the pressing method. The instructions for use for the consumer are also based on these parameters. Group A (extrusion) tiles should only be laid with open joints, while Group B (pressure) tiles can be laid with both open and closed joints.

Unglazed or glazed tiles

And finally, the surface of the tile is also a very important selection criterion. On the one hand, glazed ceramic tiles have a wide range of colors and patterns, on the other hand, unglazed ceramic tiles are more uniform throughout the entire thickness without variations or interruptions in color across the entire surface and thickness of the tile. Directions for use are obvious, especially if high strength is required in conditions of strong abrasive influences on the tiles.

It should be noted that the standards for glazed tiles do not define requirements for many characteristics. In this case, the requirements must be determined point by point, by mutual agreement between the manufacturer and the consumer (seller and buyer). Let's take a typical example: the abrasion resistance of glazed tiles. In this case, all six resistance levels adopted by EN 14411 are acceptable (from class 0, which defines the requirements for no abrasion, to class 5, which defines the requirements for deep abrasion). In this case, the user must clarify the necessary requirements, depending on the operating conditions.

Conclusion

Repeating the importance of a correct understanding of all the properties of the tile, it should be noted that the tile is only the surface layer of the cladding. Wall and floor cladding is a complex multi-layer system consisting of ceramic tiles, cement-lime mortar or adhesive mixture that form the base; it is also possible to have a separating layer, hydro-, thermal and sound insulation and sub-cladding structure. External conditions influence and are reflected in the entire cladding system. Choosing tiles with appropriate characteristics is certainly important, but not the only condition for the strength and durability of the cladding. Careful preparation and proper arrangement of floors and walls are required.