A terra-cotta tile is a porous tile made from clay and fired at low temperatures. Specific types of tile are made in the terra-cotta method, such as Saltillo tiles which are made from clay found only in Saltillo, Mexico; however, the connecting factor is that terra-cotta tiles are typically chosen for their rustic, old-world look. Grouting terra-cotta tiles is no more difficult than grouting ceramic tiles and, in fact, due to their organic nature, terra-cotta tiles might require less perfection in grouting than other types of tile.
Allow the tile adhesive to cure for a minimum of 24 hours.
Use a spacer puller or needle nose pliers to remove the plastic spacers from in between the tiles.
Brush free any loose adhesive in the joints, and vacuum all debris from the surface. Wear your knee pads and gloves for safety and protection.
Mix the grout according to the manufacturer's instructions. The experts at Hammer Zone recommend sanded grout for floors and other applications where there is a wide grout seam between tiles. Non-sanded grout is used when tiles fit very tightly together such as in a shower stall.
Lightly mist your working space with water from the spray bottle. A thin layer of water will help the grout move over the tiles more easily. Scoop approximately 1 to 2 litres (1 to 2 quarts) of grout onto the tile. Hold your grout float at a 45-degree angle, and spread the grout over the tiles in a sweeping motion. Press the grout into the tile joints until they are completely filled.
Change the angle of your grout float to 90 degrees, and slide it over the tiles in a diagonal direction to remove excess grout.
Allow the grout to harden for approximately 20 minutes. Use a clean, wet sponge to remove even more excess grout. Carefully smooth out the grout lines with the moist sponge as you clean. Keep a bucket of clean water nearby, and rinse your sponge often. Change the water frequently.
Use a dry, soft cloth to clean the remaining haze from the tiles after the grout has hardened. This may take 2 to 24 hours depending on the type of grout used and your environmental conditions.
Seal the completely dried grout with a commercial sealer. Follow the manufacturer's instructions and use a small paint brush for easy application.
Apply the grout to a 90 x 90 cm (3 x 3 foot) section or an area in which you can comfortably reach the perimeters until the entire project is finished.
Seal terra-cotta tiles before installing them. Unsealed terra-cotta may be stained by grout or adhesives. Grout, especially sanded grout, can be very drying to the skin. Always wear protective gloves while you are working with grout.