First I want to thank all those that replied to my question about hardwood flooring over OSB.
Now I am ready to put some floor tile over 3/4 T&G OSB. In the past when I applied Duraroc over plywood I used thinset mortar and screws. All of the thinset I have sen recommends NOT using it over OSB. I was planning on putting down 1/4 Duraroc over the OSB as a subfloor for the tile. Do I need to have some type of glue for the duraroc or can I just screw it to the floor joists applying it across the OSB joints? The TJI floor joists are 16 on center.
Any suggestions for applying floor tile over OSB??
Thanks
Replies
I use Hardibacker. I have put it down without mortar under it and have been fine. If my tile guy is putting it down he will mud under it.
I wonder why cement board doesnt want OSB under it? Its a stable material and pretty much the standard subfloor in alot of areas.
cement board doesnt want OSB under it
That's not what he said. he said the thinset mfgr doesn't recommend going over osb. I wonder if it has to do with the moisture in the thinset affecting the wood."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
OSB will delaminate from the moisture, causing it to become weaker.
I've used Durock without thinset a few times and have had no issues so far. I screw it about every 4" and it's down about a solid as it gets.--------------------------------------------------------
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Mapeprime™1K?
(...a silane-modified, solvent-free, water-based epoxy primer forenhanced adhesion to porous and nonporous substrates before the applicationof tile-setting materials, underlayments and toppings. Utilizing the latesttechnological advancements in silane coupling agents, the one-componentMapeprime 1K is easy to apply, fast-drying and high-performance on a widevariety of surfaces.)
http://www.mapei.it/Referenze/Multimedia/Mapeprime1K_TDS_EA.pdfView Image “Good work costs much more than poor imitation or factory product” – Charles GreeneCaliforniaRemodelingContractor.com
It looks like a great product for adhesion to non-porous surfaces, but the issue is osb's resistance (or lack there of) to moisture. They did mention plywood but nothing about osb. --------------------------------------------------------
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Gee, thanks Ted for reviewing those salient points. OSB you say? Hmmm. The product I referred to is for "enhanced adhesion to porous and nonporous substrates" (and last I checked plywood and concrete are porous surfaces - as is OSB, no?).
Mapeprime 1K is billed as a fast drying water based epoxy primer. I don't know how it would perform over osb, but if the conditions were favorable to a quick drying time, I would think it should work fine, both as a moisture blocker and a bonding agent.
View Image “Good work costs much more than poor imitation or factory product” – Charles GreeneCaliforniaRemodelingContractor.com
Edited 5/2/2008 11:46 pm by Huck
"Mosture Blocker" is the functioning phrase, which isn't mentioned in the pamphlet.
It probably is a good solution, but best to make sure. I'd hate for all that tile to crack because the osb swelled up and became mushy. I recenty set large porcelain tiles over sealed slab and the thinset was still wet 4 days later when I replaced one tile. that's plenty of time for moisture to find it's way into osb and turn it into mulch.
I'm guessing that salient product (and similar products) will seal the osb and prevent that from happening, but that's just my guess and I was wrong once before :) If I went that route I would do 2 coats just to be sure.
Another option would be to spread Liquid Nail (1 gallon cans) with a notched trowel. --------------------------------------------------------
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