The tile is the last layer. The layers under it decide whether it stays.
Plan the whole build-up before anyone mixes a bag: the support, the movement joints, and the binder that matches the body of the tile. A careful drawing still fails if the bed is the wrong one.
Once that is settled, the work on site is a short sequence. Skip a step, or rush the open time, and the usual defects follow — hollow spots, lippage, stained joints, tiles that release.
Fully vitrified porcelain barely absorbs water, so a conventional cement bed has little to key into. Specify an improved adhesive to EN 12004 or ISO 13007-1, with a minimum bond of 1 N/mm². Naming “adhesive” on the drawing is not enough — the class has to be the right one, or the tile still lets go.
Ceramic that takes up water can be laid in a thick cement-sand mortar. An adhesive bed is also acceptable, and usually costs more. If the ceramic is going into a wet or heavily trafficked room, confirm the method with the project team before the screed is poured.
Clean, sound, and flat enough for an even bed.
Mortar for porous ceramic. Improved adhesive for porcelain.
Compact a thick bed, or comb a thin one with a notched trowel.
Press, check full contact, and keep the joint open.
Fill completely. Colour the grout to the tile, or specify epoxy where the room demands it.
Remove residue while it is fresh. Do not load the floor until the bed has cured.
The support must be clean of dust, paint flakes, grease, oil, and anything that lifts with a fingernail. Sweeping is rarely enough. Wash it.
It also has to be flat. An uneven screed forces the adhesive thicker in some places than others, and that difference becomes stress as the bed cures. Floors that will take trolleys or vehicles need a rigid support, reinforced where the load requires a distribution layer.
Judge the finished work on two things only: how firmly the tile is held, and how regular the joints are.
The tile must hold to the bed, the bed must hold to the support, and the bed itself must stay cohesive. A hollow sound is a gap, not a finish.
Joints should be regular, full, and even in colour. That is what keeps the field looking deliberate, and what lets the surface move.
Cement grout, tinted toward the tile, is the usual joint. Latex, acrylic, and epoxy grouts exist for rooms that need them — pools, kitchens, chemical exposure. Pack the joint full with a rubber float. Do not smear it and call it filled.
Clean while the grout is still fresh, with a damp sponge, without dragging material back out of the joint. A later rinse can lift cement haze. Mild diluted acid is sometimes used for that haze, and it will etch a polished porcelain face. Know the surface before anyone opens a bottle. Neutral cleaner is the safe default.
The bed still has to cure. Follow the adhesive manufacturer’s waiting time. Where the bed is cement mortar, allow at least 20 days before normal use. Loading it early is how a correct installation becomes a defect.
