The success of porcelain tile is not only due to the technical and a esthetic quality of the material, but to a number of other factors(surface to be covered, intermediate layers, adhesive, expansion joints...)making up an entire system.
Features of floor or wall
Prior to laying or hanging ceramic tiles, the floor or wall should be examined to ensure a stable base. The surface to be covered must be level, firm and free from substances which might preventthe adhesive from binding.
The main characteristics to considerare the finish and surface condition of the floor or wall, whether it is smooth and even, its capacity for water absorbtion, deformability and dimensional stability, reaction to water and humidity and its chemical compatibility with the adhesive to be used.
If the condition of the floor or wall fails to fulfil the requisites for laying or hanging, or major structural movement is foreseen, this should be solved by adequate treatment of the surface to be covered and/or using sliding layers, levelling, reinforcement and/or insulation layers and suitable provision of dilation or movement joints intended to absorb the various degrees of pressure generated by movement of the substrates and structures.
In the case of recovering existing ceramic surfaces it is advisable to treat the surface in order to create areas which will help the product to adhere.
Placing and movement joints
Strict observance of the 1.5mm minimum joint between floor tiles is essential, with a wider joint being recommended for medium and large formats, thus allowing absorption of the differential pressure produced in the multi-layer floor/adhesive/tile system.
For large surface areas it is advisable to divide the floor into 4x4 metre sections,introducing elastic expansion joints (partition joints).
In any case, it is wise to leave agap between the flooring and existing elements such as walls, pillars and raised levels(perimeter joints), intended to prevent pressure from accumulating. This gap can be covered later by the skirting tile. The absence of these joints is usually one of the most frequent causes of loose floor tiles.
Features of porcelain tile: laying or hanging techniques and adhesives
Since these tiles have a very low water absorption capacity, it is essential to use adhesives compatible with low porosity. The "thin bed" laying technique should be used, with adhesives suited to the open porosity of the tile and compatible with the surface to be covered. For non-residential applications it is advisable to use cement-like adhesives with a high polymeric resin content, dispersion adhesives or reagent adhesives, depending on the floor surface requirements and the atmospheric conditions.
In any case, high levels of adherence, flexibility and good resistance to water can be considered normal demands, plus high chemical resistance for industrial applications. These recommendations can also be applied to the grout, which is usually expected to be elastic and offer high mechanical and chemical resistance.
To ensure a correct use of adhesives, the manufacturer's instructions for preparation and application must alway sbe followed, respecting the times indicated.
Owing to the low water absorption of glazed gres porcelanico, which delays drying time for the adhesive being used, a 48-72 hour wait is recommended before subjecting the floor tiles to normal use. In the case of polished products, avoid using pointing materials containing soot black (micronized carbon) or making pencil markings on the surface of the tiles as this may cause difficulty when cleaning the tiled surface.