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I am used to doing 3/4″ T&G Ply as Sublfloor, then 1/2″ Wonderboard under the tile.
My sub wants me to use 1″ Ply, and he will use 1/4″ Hardibacker over that. I guess the rationale is that the extra 1/4″ of wood is stronger than the backer board.
Do any of you have any experience on this technique? Thanks!
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Replies
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Tommy,
I don't have any specs on this, but I use 7/8" OSB T&G with 1/4" Hardiebacker. I found the 7/8" product to be cost comparable to 3/4"ply and strength and stability compared to 1"ply. I like the 1/4" Hardiebacker because it is a much smoother and more even surface to lay the tile on to. I also found it was better for setting the screw heads (reduces the chance of a pop-up). I also prefer the way the Hardiebacker cuts. It leaves a much cleaner break than the often jagged line I get with the wonderboard product. On my next house, I plan on using radiant floor heat and laying the tile directly on the concrete. It makes a very comfortable surface to walk on when it's -20F outside! Good luck on your project!
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I think your logical choice will be 7/8 or 1 1/8" plywood. 1" is not common for subfloors. I have used 5/8" with 1/2" backer board without problems, but this has been in existing situation where there was no choice. You will get some value out of 1/2" backer board, but none with 1/4". My choice would be 7/8 plywood and 1/2" backer board. But....your chances of having problems from joist deflection are probably greater than from sheathing deflection between the joists. Consider larger joists or smaller centers. In any case go no more than 16" oc.
*Hardibacker is also available in 1/2" sheets which tend to be more rigid than either Wonderboard or DUROCK. Wonderboard is however available in 1/4" thickness that is specifically designed for flooring. C/DX plywood sheathing screwed and glued on 16" centers is a suitable substrate for any cementious backerboard product. The key here is the size of the floor joists supporting the plywood and backerboard substrate. Assuming adequate structural support, you should be fine. Remember to run a layer of felt under your backerboard. An alternative installation procedure which would guarantee a strong, level floor surface is to install diamond metal lath over a felt membrane nailed every six inches, and then apply a medium bed self-leveling compound. It's quick, and very strong over 3/4" C/DX.
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I am used to doing 3/4" T&G Ply as Sublfloor, then 1/2" Wonderboard under the tile.
My sub wants me to use 1" Ply, and he will use 1/4" Hardibacker over that. I guess the rationale is that the extra 1/4" of wood is stronger than the backer board.
Do any of you have any experience on this technique? Thanks!