I am putting a ceramic shower on a cement floor. I plan on putting a sloped cement floor from 3/4 to 2 inches under the ceramic. My question is why do I need a pan liner? Can I just use cement on cement under the ceramic? It seems that the ceramic should be waterproof. Thanks
Absolutely NOT! Tile & grout is waterproof in that water does not hurt it. That does not make it waterproof so water doesn't get thru.
You need to study and understand how a shower should be built, and why. I would rather see you build a real "waterproof" & "watertight" shower. Kerdi membrane with the Kerdi drain is the answer. http://picasaweb.google.com/tile4youinc
TILE GUY - retired- TROY, MI - Method & Product suitability consulting.