After the tile is firmly set, apply a polymer wall grout. This grout just requires the addition of water, no latex additives, because it already contains polymer additive to improve strength, adhesion and flexibility. Mix to the consistency of heavy peanut butter. Using a rubber or sponge float, apply the grout working diagonally across the tile joints. Pack joints making sure there are no voids. Holding the rubber or sponge float at a sharp angle to the wall, but still working diagonally across the tile joints, remove as much excess grout as possible.

Wait 15 minutes to allow grout in joints to firm up. Then carefully sponge off excess grout on the tile using a DAMP sponge. Rinse sponge frequently and wring out thoroughly.

After 2 to 3 hours, polish the tile surface with a clean dry cloth to remove the slight film left by the previous cleaning steps.