Quarry tiles are an extremely dense and durable red clay tile. They can be left glazed like ordinary ceramic tiles, or left unglazed to allow their natural colour to show through. Quarry tiles can be grouted in a similar fashion to other tiles, using the same materials. Because many quarry tiles are installed on floors and other high-traffic areas, sanded grout is most commonly used to help give a larger, more durable grout joint to the job. The grout can be spread with a standard grout float.
Pour dry, sanded grout into a large bucket. Begin slowly adding the amount of water recommended by the grout manufacturer to the dry grout, stopping frequently to mix the water in with a trowel. Stop mixing and adding water when the grout reaches the consistency of natural, gritty peanut butter.
Scoop a tangerine-sized amount of grout onto the quarry tiles, using a grout float. Hold the float so the edge meets the quarry tiles and the flat of the float sits at a 45-degree angle above them. Drag and push the grout with the float at this angle across the surface of the quarry tiles into the grout joints.
Make several, short drags with the float across the quarry tiles to help bring up as much grout as necessary and direct it to the joints. Quarry tiles may be gritty or rough in texture; several short passes with the float will be more effective than longer passes.
Press the float flat against the grout between the quarry tiles to pack it into place. Move the grout into the joints from all angles to ensure good coverage. Let the grout dry for 10 minutes.
Clean the quarry tiles with a slightly dampened sponge. Rinse out the sponge frequently and rub it in small circles over the quarry tiles to free them of excess grout. Hold a loose, clean quarry tile up to the installed tiles frequently to compare colour and check for grout haze. Continue cleaning the quarry tiles until no haze remains and the installed tiles match the loose tiles in colour.