I used white grout for the walls, and gray for the grout line along with floor. I started with the white for the walls, and will let that cure overnight before I add the grout to the floor seams.
The grout I used is a premixed ceramic tile adhesive and grout (made by Tile Perfect) and worked it into place with a gum rubber grout float. First I used a plastic putty knife to take the premixed grout from its container to the grout lines on the walls. (The plastic putty knife won’t scratch the tiles, like a metal putty knife could.) Once a generous amount of grout is along the grout line, I took the rubber grout float and pulled it along the seams at a 45-degree angle (the float itself should also be held at a 45-degree angle to the surface of the tile) to work the grout in between the tiles.
Once the grout is in place, I removed the excess grout with a sponge, being careful to remove all grout from the face of the tiles so a haze isn’t left behind. It’s helpful to have a good-sized bucket of water on hand. The larger the bucket of clean water the better, because you’ll want to wring out the sponge frequently.
If you enlarge the photo to the right, you’ll see the bright white grout in the vertical grout line in the corner. It extends down to the floor, but come up a little short of the floor grout line. I’ll add the gray grout up to meet the white wall grout. You can also see the white marine epoxy along the floor joint, and under the corner below where the missing floor tile (which will be re-installed with the gray floor grout).
Again, I’ll let this grout cure overnight before applying the grout to the floor. There’s only one area were the floor and wall grout meet – the trouble spot in the front corner of the shower – so I want to give the white wall grout time to cure a little before the gray floor grout comes into contact with it.
Overall, the manufacture suggests that the grout cure for 48 to 72 hours before regular (shower) use. Tomorrow, grey floor grout. Then hopefully I can get back to work on the upstairs bathroom.