Choosing the installation team
Mistakes to avoid
Installing without joints is one of the most common mistakes. This usually happens because the customer wants a particular aesthetic. From a technical standpoint, though, installing with joints is recommended. For small or medium tiles, a 1-3 mm joint is recommended, and for large tiles, 5 mm or more.
Here are the main reasons why:
thermal expansion – this property of stone mainly shows up in exterior cladding, due to freeze-thaw cycles, and in interior cladding in areas with significant temperature swings. On average, stone tile dimensions vary by very small amounts (under 1 mm), but with jointless installation (tiles glued edge to edge), that’s enough to cause damage over time, as tile edges grind against each other.
dimensional differences between tiles – these differences are hidden by joints. With some installation layouts, alignment differences appear that, to be corrected, require cutting tiles, increasing labor time and cost.
surface tension from installation – this is absorbed by the joints, which also let the adhesive (mortar) “settle” properly.
replacing a chipped or damaged tile – this is difficult to do with jointless installation.
Choosing between traditional mortar and adhesive – this is a mistake that happens when the porosity of the substrate and the tiles isn’t assessed. If both have high porosity, traditional mortar can be used (e.g. for sandstone or travertine cladding). But if at least one of the two surfaces in contact has low porosity, an enhanced mortar or specific adhesives are needed (these contain the necessary chemical components, usually polymers).
Not following proper installation technique
for stone tiles, the accepted technique calls for spreading adhesive over the surface with a notched trowel, “combing” the adhesive layer. This technique is needed to ensure adhesion by eliminating air pockets on the surface. The “dabbing” technique, used for ceramic tile cladding, encourages air bubbles to form, which reduces adhesion.
another installation mistake comes from poor adhesive coverage on tiles. For dry cladding, the minimum recommended adhesive coverage is 85% of a tile’s surface; for cladding on a damp surface, the minimum coverage is 95% of the tile’s surface. Without enough surface coverage, adhesion suffers.
large tiles, with a surface over 900 cm² (tiles larger than 30 x 30 cm), are bonded by spreading adhesive on both the tile and the substrate. Not following this technique reduces adhesion, and the result is tiles coming loose, especially on walls.
Removing excess grout from the tile surface after the grout has dried – this is a common mistake that leaves behind dried, hardened grout residue on the surface. This isn’t easy to remove and requires strong detergents to clean off. That’s why the surface should be cleaned before the grout dries, using a damp sponge.
Applying sealant before the grout has dried – this mistake spreads the grout out of the joints and stops the sealant from adhering to the surface.
Applying adhesive and grout over large areas – it’s best to avoid applying these over large surfaces, since they can set before related steps are finished, such as leveling the surface, correctly positioning tiles, or cleaning off grout. It’s also recommended to avoid foot traffic on surfaces that have just been tiled or grouted.
