Substrate preparation

Preparing the substrate is always necessary, and the result must be a smooth, clean, dry, load-bearing surface.

For drywall walls, preparation must account for the fact that they can only support about 25 kg, which rules out large stone tiles, whose weight combined with the adhesive exceeds that. Cleaning the surface by removing any residue improves adhesion. If the wall is being reused, it must be checked for surface stains (paint residue, grease stains), and any traces of wallpaper or posters must also be removed. Checking the integrity of an old wall is essential to ensure it can bear the needed load. New walls also need good adhesion.

These should have a rough surface (sanded with medium-grit sandpaper), and a primer should be used to even out water absorption and increase adhesion. Adhesives are chosen for bonding based on tile size and where they’re being installed.