Let your newly installed ceramic tiles set for at least 24 hours. Get the tops of the tiles thoroughly clean and free of any residual mortar. If there's any mortar piled up in the spaces between the tiles, dig it out with your putty knife and blow it clear of the lines.
Put about 2 inches of water in a bucket. Add enough grout mix to cover the water. Mix thoroughly with your putty knife. Add more water and grout mix, alternately, until you have enough grout to do the whole tiled area and it's the consistency of thick mud.
Allow the grout to "slake'' in the bucket for about 10 minutes, so the compounds can soften and dissolve. Re-stir the grout with your putty knife.
Scoop up a trowel-full of grout with your grout float and apply it to the tiles. Wipe the grout with the float, holding the long edge of the float at about 45 degrees as you drag it across the tiles. Press the grout into the lines between the tiles, making sure they're all filled.
Let the grout sit in the lines for at least 10 minutes, but not more than 20. Dampen a sponge and wipe across the tiles gently to take up the excess grout from the face. Make sure that only the flat part of the sponge (not the corner of the sponge) moves over the grout lines, so it smooths out the grout surface without digging it out of the lines.
Let the grout sit for another 30 minutes. Re-wipe with the sponge, more vigorously this time, to take up any loose grout or uneven ridges from the grout lines. Wipe once or twice more, after 30-minute intervals.
Things You Will Need
- Ceramic tiles
- Grout mix
- 3-inch putty knife
- Grout float (flat rubber trowel)
- Wide, flat sponge
- If you're grouting a large floor, work in sections of about 6 square feet, laying the grout in one section. Let it sit in the lines as you lay the grout in the next section, while wiping up the first section.