Granite tile is a stunning, natural-looking addition to nearly any surface in your home, and can add a breathtaking decorative touch to walls, floors, counters and anywhere else you can think of. Granite tile is extremely heavy, and if the adhesive or thinset mortar used to hold it in place does not cure properly, you can be facing serious slipping or future damage.
Thinset Drying Time
The thinset mortar used to hold granite tile in place requires at least 24 hours to cure fully before you can apply grout. This time can vary depending on conditions in the installation area, including temperature and humidity. The higher the humidity, the more moisture in the air, which keeps the thinset curing longer. The higher the temperature with low humidity, the faster it will dry. In general, if the room in which you have installed the tile features a humidity level above 70 percent, allow an extra 12 hours of curing time before applying grout.
Wait to Grout
If in doubt, wait longer to grout. The reason is simple: grout also contains moisture. If you apply grout to a surface on which the thinset has not fully cured, the adhesive will absorb moisture from the grout. This can result in slipping of tiles, due to the softening adhesive and to the grout drying unevenly, causing cracks in the grout surface that will not only mar the appearance of the grout, but also ruin the seal intended to keep water out.
As the thinset cures, the heavy tile may shift, especially on vertical installations such as walls or countertop edges. For this reason, keep all traffic off the granite tile until the thinset has fully cured, and then again after the grout application until the grout has fully cured. For these vertical surfaces, use masking tape to hold the tile in place, anchoring it to a solid area nearby to avoid slipping and sliding of the material from the surface.
Types of Grout
Once you are ready to grout, you will need to carefully choose your product. The granite tile’s manufacturers will dictate the minimum space required for grout lines in the installation. If you want the lines to be wider for decorative purposes you can spread them out, but you can’t make them smaller. Once the grout lines are established (and held open by spacers while the thinset dries) you know what type of grout you need to use. Unsanded grout is intended for grout joints 1/8 inch wide or smaller. You can use sander grout, which features larger particles, for larger joints to effectively fill in the area.