Installing different shapes and tile material to your walls can often result in the smaller tiles, likely made of glass, to be a different thickness than ceramic tile. The average do-it-yourselfer can correct this problem with the proper tools and by following a few simple instructions.
Things You'll Need
Lay out the tiles to set up a dry run to get a better picture of where certain tiles will go. This allows you to see exactly where the tiles of lesser thickness need to be placed.
Spread the thin-set mortar with a notched trowel to a small area that will allow you to install only a handful of tiles. Thin-set can dry quickly and lose its adhesiveness.
Apply larger tiles to the thin-set first, by twisting them into place to make sure they adhere to the thin-set. Place you desired width of plastic spacers between the tiles.
Cut a waterproof membrane, like Ditra for example, into small sections to fit exactly under the smaller tiles to compensate for their lesser thickness.
Install a few strips of Ditra to your wall or substrate area, depending on where you are installing the tiles. Add a layer of thin-set onto the Ditra, and apply the smaller tiles to the thin-set like your first batch of tiles.
Use a level to make sure your tiles of different thickness are completely level on the wall or on the floor.
Repeat Steps 2-5 until your working area is complete, remove the plastic spacers and allow 24 hours for the mortar to set.
Apply grout with a rubber float in between each tile to fill every nook and cranny. Use a damp sponge to remove excess grout, rinsing the sponge thoroughly from time to time.