I hired a relative to install tiles on the living room last May 05, and already I had to remove over 200 tiles. I'm presently removing and installing more. The real problem is that over an inch of thinset was used to level the floor and since water has sipped through, the grout is cracking and the tiles are coming out. Instead of thinset, can I use portland cement. Also, was is a good grout to use that can prevent water from sipping through. Help, 'm doing this myself now.