On my additon floor I will be using 16″ on center floor joists. with 1″ 1/8″ doug fur
t and g plywood. I am tiling the bathroom floor in one section. Do I need to use a backer board or you think I am good to install on ply? I was think Ditra would be a great choice here myself just to help with any movement issues but If i can save money I would install on ply if its good enough.
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Replies
What is the span and size of the floor joists? That and the oc spacing will tell you if the floor is stiff enough. If not, the cement board will not help ... it does not add any strength, only provides a good bonding surface. If the deflection is marginal, ditra can help without adding thickness.
"Put your creed in your deed." Emerson
"When asked if you can do something, tell'em "Why certainly I can", then get busy and find a way to do it." T. Roosevelt
2X12 SPACED AT 16" 0C AND A SPAN OF 14' WITH 1" 1/8 DECKING. I AM SURE THATS OK ITS THE BONDING i WAS WONDERING ABOUT.
Your floor deflection calculates to L/617 which far exceeds the L/360 required for ceramic/porcelain tiles, so that won't be a problem. You don't quite meet the L/720 needed for natural stone."Put your creed in your deed." Emerson
"When asked if you can do something, tell'em "Why certainly I can", then get busy and find a way to do it." T. Roosevelt
I'm no pro, but I get a bit skittish thinking about tile in a bathroom, just on ply. I recently ripped out a bathroom that had that (much less support, but that's not my issue) because the water had seeped through and soaked the ply to the point of failure. I'm not personally familiar with Ditra, but if it creates a waterproof seal, I would consider it.
You ever try to get tile off of plywood? Its takes the plywood with it.
http://WWW.CLIFFORDRENOVATIONS.COM
If you're just concerned w/ the waterproofing (and from how you describe the floor structure, that's all I'd be worried about), there are plenty of trowel-on waterproofing products as well as membranes (Ditra is great, but maybe overkill here). I'd just pick up a trowel on and be done w/ it.
Recently found a roll on waterproofing membrane at H.D. of all places. Its a blue rubber type that can be applied witha roller. The wall sheathing has to come right to the floor so you can roll up a couple of inches, other than that, I'd go right over the ply. I like theDitra product, but for a small bath, I don't think its necessary.
Recently found a roll on waterproofing membrane at H.D. of all places. Its a blue rubber type that can be applied witha roller<<<If youre talking about that peel n stick stuff...its real crap...I know two people that "tried" using it. Ditra is the REAL DEAL!
http://WWW.CLIFFORDRENOVATIONS.COM
Not a peel and stick, a rubbery liquid that you apply with a paint roller. We used it ontop of the drypack ( with vinyl membrane under ) as another layer of protection. Thinset sticks to it and for the OP, I thought it might be enough for his purposes.
I also like the Ditra, used it on my place.
Probably thinking of a Laticrete product? (9235) I just used it in my shower, over everything else (pvc liner, mud bed, vertical durock board) as a final prep before tiling. Waiting for it to cure before finishing.
use a backer or sanded plywood (AC grade), assuming your 1 1/8" deck is CDX doug fir sheathing CDX is not meant for tile substrate, some lumber yards post itso seen it used like that lots, but why take the chance skip waterproofing the base, it's a place for mildew to grow, and any transient dampness should be allowed to dry from below use a sealer on the tile after the job or just on the grout lines use a good sealer from a tile house or supplier, retail about $65. quart if there's lots of water going thru a tile floor, fix the damaged grout or opening it's going thru and correct the "swimming pool" condition causing it such as leaks, etc
Edited 5/3/2007 11:54 am ET by vinniegoombatz