Does anyone have any suggestions about this: I am considering installing 1″ thick unpolished granite tiles (24″x24″) on a kitchen floor. In the past I have installed 5/8″ thick tiles over a cement backer board with latex based thinset. Over a firm subfloor, this combination seems to provide enough stability to keep the tiles from cracking. I am wondering if I can skip the backerboad if I am using 1″ thick tiles since they are probably as stiff, if not stiffer, then the 5/8″ tile over backerboard.
Any feedback would be greatly appreaciated.
Ernie
Replies
I would not install natural stone directly to plywood. There is just too much movement in plywood. Tiles may not crack but your grout will. Thinset also doesn't bond as well as it could with plywood. Another setting bed is perferred.
I would either use a setting bed of mud, Hardibacker, or Ditra, depending on your elevation issues.
Boris
"Sir, I may be drunk, but you're crazy, and I'll be sober tomorrow" -- WC Fields, "Its a Gift" 1927
Thank you Boris. Elevation is my main concern here, I was trying to avoid creating an 1.75" thick floor. But I guess I may have no choice.
Thanks again for responding.
If elevation is an issue, then select Ditra which is only about 1/8" thick, and provides a nice setting bed while uncoupling the tile from plywood. 1/4" Hardibacker would be another nice choice.
Regards,
Boris
"Sir, I may be drunk, but you're crazy, and I'll be sober tomorrow" -- WC Fields, "Its a Gift" 1927
I'm not a tilesetter, but I have been around hundreds of floor jobs with only 3/4 subfloor and 1/2" ply underlayment, no cementicious board, and no cracking...I'm not recommending it, just passing along an observation of regional practices...I also have floors in my own house done the same way, no cracks, no runs, no errors... It's okay, I can fix it!
the TCA handbook shows that set up....3/4 sub and 1/2 exterior ply.....specifies latex-portland mortar...so it must not be too out of line.
But if I was going 1/2 inch ply.....I'd switch to 1/2 inch CBU. Just as insurance.
Jeff.......Sometimes on the toll road of life.....a handful of change is good.......
Granite is not stiff. It is great in compression but but is brittle and breaks easily in shear such as on a floor. I would also be concerned about using a thin set. You may need a medium set that allows a thicker bed so that you can level the tiles and prevent lippage (one edge higher than the next tile). I doubt that the tiles will all be flat and a consistant thickness. Just my experiance with 1/2" granite and 3/8" slate 12 x 12 tiles. I found out the hard way that gaged as it relates to stone tiles only means that back has been kinda flattened not that all of the tiles are the same thickness or that they are flat.