Application Apply the mix to the surface, 1m2 at a time, and rub the grout well into the joints using a grout squeegee, making sure that the joints are properly filled. Wipe off excess grout and smooth the surface of the grout with the squeegee. Allow the grout to harden sufficiently (approximately 2 - 6 hours, depending on ambient conditions) to prevent accidental removal from the joints. Using a damp (not wet) sponge, clean off any grout remaining on the face of the tiles. Rinse the sponge frequently in clean water. Allow the grout to dry for 24 hours and polish the tiles with a clean, dry cloth. Clean tools before the grout hardens.