My husband and I are planning to remodel our shower, and we have run into a snag. Our shower currently has a fiberglass shower pan and 4 inch white ceramic tiles on the walls. We are planning on making our shower larger by removing the existing shower pan and creating a new shower floor with 1x3 tiles. We plan to extend the new tile about a foot up the wall, and keep our existing tile on the rest of the wall. As my husband started removing some of the tiles from the bottom of our shower wall, he realized that the new tile that we were planning to buy is thicker than our existing tile. So, the part of the wall with the new tile will stick out quite a bit more than the rest of the shower wall. We have concrete behind our existing tile. Is there any way to install our new tile so that it is flush with our existing tile? Any other suggestions on how to address this issue?
You are going to need a waterproofing membrane under the floor of the shower and extending up the walls about 8". Otherwise as the water migrates through the grout and into the cement under the tiles it will go to places it should not go. The new pan will be a self contained unit that keeps the water inside the unit and directs it to the drain via weep holes in the base of the clamping flange and employs a preslope so that water does not stand and become musty in the cement bed. I know I am throwing some lingo at you that you may not understand. Rather than bore you with the details here go to www.ontariotile.com and look at their section on building a shower pan. It will explain in greater detail what I have talked about.
To answer your other question about the transition from on thickness of tile to another, try inserting a decorative pencil strip or something similar between the two different tile. That way it will serve the purpose of a transition and also look like it was meant to be that way. Go to your local tile retail stores and ask to see pencils and ropes, they should know what you are asking for.