Frequently asked questions

What to know about expansion joints

In addition to the regular joint width, the expansion of the floor must be taken into account both indoors and outdoors. Non-adhesive or floating floors are most commonly used indoors. This means that the structure of the floor was placed separately from the insulation or substrate and can and will therefore move freely. The joints, with small surfaces, absorb these stresses. It is also perfectly normal for the joints to have small cracks here and there or for a small gap to form between the joint and the tile. The joints performed their function perfectly here. If the cracks continue in the floor tile, the tensions are too big. The cause is either the lack of expansion joints or a destabilization of the substrate. The tile itself is never the problem here. Giant sills in old houses 15 cm thick and 40 cm wide break in two like a twig, because they were too long and could not withstand the stresses.

Where do I need expansion joints ?

From experience, we know that for regular interior floors, one flexible joint is needed per 8m (length) and 50m² (surface). In case of floor heating, one per 7m and 40m². For exterior floors, the maximum values are 6m and 36m² for light-colored tiles and 5m and 25m² for dark-colored tiles. For patterned floors and floors where the grout touches the tile, the minimum values must always be complied with, despite the rules above.

What grout width do I need to keep ?

Our product data sheets include the recommended grout width for each type of natural stone. Sometimes, there are variations, for instance a grout width between 2 and 6 mm. How should you proceed in those cases?
If the sides of the sawed materials are perfectly square and smooth, you can use thin grout lines. If your natural stone has a coarse finish and/or coarse edges (tumbled or pitted surface) you need a larger grout line. Please get advice on the required grout width for your stone, with its specific finish, for your specific application. Your floorer will refuse if you ask him to install a tumbled surface floor with 2mm grouts. Conversely, it is a matter of personal taste if you want to have a grout of more than 6mm wide for your perfectly sawed tiles. As the dimensions of natural stone may vary very slightly, the grout width can compensate these variations in an esthetically sound manner.
The rule of thumb for grout width is the size difference in squareness + 2mm (+ 1mm for tolerances during installation or exterior applications).

What color of grouting should I use?

Grouts are a necessity, but they also have esthetical value. Especially for smaller surfaces, the color of the grouting has a major effect on the overall look of the floor. A dark tile with dark grouting looks completely different from that same tile with a light grouting. The mortar must necessarily have the same composition and consistency everywhere. Slightly less or more water can make for a different grout color. As such, please follow the instructions regarding the proportions, mixing times, waiting times, and processing times.