My 5x5' bathroom floor currently has 5/8" plywood, 1/2" cement board, and 12" ceramic tiles that I laid about 10'years ago that still looks new. My joists are 2x8" on 16" centers and unaccessable from below because of finished ceilings. We are now renovating almost down to the studs, therefore a new floor is in order. Our choice is travertine but a contractor friend is advising agains it due to structure. He tells me that I need to double up each joist and lay 3/4" plywood. We also want to install a cast iron tub that weighs 325# and we plan to use travertine in the shower stall as well. What is your option of his structural requirements? Also what is your opinion on this plastic matting that the tile stores are recommending instead of cement board?

Hi, We moved into a 15 year old house in Florida a few months ago. I noticed the grout popping & cracking around about 8 tiles in the kitchen. The tiles are 20" x 20". I tapped on a few of them and they sounded hollow, so I thought it was just a bad Thinset application. I just took a few of them off and they were Thinsetted to some sort of mesh fabric sheet. It's very tough stuff, I had to cut it with a utility knife. The fabric was not adhered to the concrete. There was a very long crack in the concrete though, so I'm guessing the fabric allowed the tiles to "float" thus preventing the tiles themselves from cracking. However, the grout cracks instead. Any suggestions? I have to re-lay the tiles now and gout them. I'm not sure what that fabric is or should I even use it. Is there something like "Redgard" that might work? Thanks