The support surface must be perfectly clean, free from dust, paint, scraps, grease and oil, friable or easily removed materials, etc. Very careful washing of the surface is advisable; in many cases simple cleaning with a broom may not be sufficient.
When the tiles are to be installed with cement mortars, the support surface must first be wet with clean water to avoid later on the possibility that the surface itself extracts part of the water from the mortar necessary for setting and hardening.
The support surface must also be chemically compatible with the binder which is to be applied for the tiling. For example, if the surface to be tiled contains gypsum, as is the case with plasterboard panels and other types of lightweight vertical partitions, and cement-based binders or adhesives are to be used, it is necessary to first treat the surface with a primer; otherwise the chemical reaction between the gypsum in the surface and the cementing component would have a negative effect on both the strength of adhesion and cohesion of the tile bed itself.
Preparation of the binder
The mortar constituents (cement, sand, water) must be carefully controlled. The sand should have a suitable particle size distribution and be clean, free from clay, organic compounds and soluble salts. The water used for tiling must also be pure, in particular it should not contain any organic matter.
Adhesives supplied with tiles in the form of powder must be mixed with water, in scrupulous accordance with the suggested dosages. Ready-to-use adhesives, only require rough homogenization with a trowel.
Application of the binder
If a layer of mortar is placed onto the support tile surface, it should be not less than 3-4 cm.
The adhesive should be applied with an appropriate notched spatula which allows a regular thickness of the aadhesive layer to be obtained as well as the realization of a surface having suitably deep groves to delineate the zones of initial contact between the binding layer itself and the tile.
The adhesive must be applied a section at a time on limited portions of the support tile surface in order to allow sufficient time for the application of the tile. Be careful when laying tiles in a hot, dry and ventilated area.
Setting the tile
When installing tiled floors, the tile should first be wetted in clean water; in particular this is essential for porous tile. The wet tile are laid edge against edge, in the case of closed joints, or against the appropriate strips of spacers, in the case of open joints. The tile should be pushed into the adhesive, taking care that the underlying mortar does not penetrate between the jooints far enough to reach the surface.
Once the tiles have been put into position, they must be uniformaly tapped into place.
When tiling tiled walls, the tiles are applied one at a time, beginning at floor level, or if this does not allow the definition of a sufficiently horizontal baseline, a strip of wood is positioned horizontally along the bottom of the wall to temporarily take the position of the first row of tiles.
When tiling large floors, it may be necessary to lay down a string from one wall to another, fixed into the ground, so as to provide a straight line to line the tiles against.
Sealing the joints The joints should only be filled 48 hours after the tiles have been laid. Various grouts are available in various colours. The operation of applying the grout is carried out using a rubber otr plastic spatula in such a way as to obtain complete, regular and compact filling of the joints.
Cleaning the freshly tiled surface This is the final operation and has the purpose of eliminating the grout and other materials used during the installation process. An initial general cleaning should be made using a wet sponge or cloth while the grouting is still fresh. This is a delicate operation and much care must be taken not to ruin the surface of the joints.
When the grout is dry, the rest of the grout can then be removed using water and a stiff plastic tool.
When the unwanted grout is completely removed, the tiles will need polishing.
It is advisable to wait at least one week after completing the project before subjecting the tiles to normal usage.