Tile contractor Tom Meehan: One thing that needs to be done before the grouting takes place is cleaning the grout joints. Any residue of thinset or mastic that is protruding from the grout joint has to be taken out.
The consistency of the grout should be just a little softer than pastry dough. I don’t want it too wet, because then it loses its strength and it won’t hold tightly in between tiles. I want to pack it in so that it’s firm enough not to sag. The key is to push the grout in, pack the joints, come across at a 45-degree angle, and clear off the residue.
It’s important to have good tools. A good grout float is made of soft rubber that’s firm enough to push the grout into the tiles and then come across. If I find that my grout float is worn down after a few months, I simply go out and buy a new one.
Right now I’m striking the grout joints. We used to use what’s called a grout stick. But I find the best tool is a Sharpie. It always stays consistent because it’s hard plastic, and it always gives the perfect grout joint. I’m packing in the joint between tiles, but even more than that, I’m making a consistent grout joint. If I didn’t do this, the joints would be wavy, heavy, thin. Keep in mind, this is only for 4-inch or 6-inch tile.
When using the sponge, rinse it out real well. I really wring it because I do not want a lot of water in the grout. Too much water will weaken the grout and wash out the joints. I turn over the sponge and keep rinsing it out so that it’s clean. If you see a joint that’s ragged and looks very rough, use the sponge to texture it and make it nice and smooth.
The final step is to wipe the haze off the surface of the tile. And I’m done.