Why do you need to Put a thinset bed under your Wonderboard, before You screw it. If you don’t does it screw you? What is the correct technique, As A base for ceramic tile.
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I am talking about New construction here.
"I was born in the country, razed in the city, I'm a natural born shaker from my hips to the ground"
I also agree with mongo on the thin set.
If you installing tile on a slab and are not using a heat strip type of floor heating system (like NuHeat) then use an EPDM membrane to keep the tile stable.
Recently put in a jetted tub, raised the flooring to accomadate the plumbing and tiled the floor.
Read the label on Hardy Backer 1/4" backerboard and it said that modified thinset should not be use (not recomended) for adhereing the backerboard to the OSB subfloor. Called the Home Depot who said something about "voids a warranty" (what warranty?). Decided to use gobs of Superman Strength Liquid Nails with plenty of backerboard rock screws.....Am I doomed to failure????
Ralph
I don't know, But I think Your lucky you didn't pass out and glue yourself to the floor. lol"I was born in the country, razed in the city, I'm a natural born shaker from my hips to the ground"
I went to the Hardi website and found this information about thinset mortars for Hardibacker:
* Latex or acrylic modified thinset (complying with ANSI A118.4)
* Dry-set mortar (use between subfloor and backerboard only) (complying with ANSI A118.1)
If you are using a thinset type mortar for your Hardibacker underlayment that meets the above listed standards then you should be fine.
I don't know about the liquid nails though. I typically stay away from the stuff, it's not always the best adhesive to use.
SDRC....did a Google search and found this.... at Ceramictileflooring.com:
To install tile or stone over plywood, you must have a minimum thickness of 1-1/8". Over 16" on center joist. DO NOT try this over 24" truss systems. It will not work! The layer to receive the flooring must be external grade plywood. NO particle or OSB board. When installing your top layer of plywood, be sure to bridge the joints of the underlying sheets. This will prevent cracking from movement in the floor. Again be sure to clean the floor as you go to remove dust. You will have to use a good latex modified thinset.
Seems to infer that you shouldn't use OSB for reasons other than adherance factors of thinset on OSB.....
One of life's mysteries I guess
RA
yeah Thanks Ralph. We used to install ceramic In the 80's. The company I worked for, Installed right on 3/4" T&G plywood -16" centers,I was told anything less will deflect. We used wonder board on the expensive jobs. We never had any problems that I know of. Theory being if you have a thin hard layer of concrete any movement will cause it to crack, eventually walking on the floor wil cause the tile to break free. I don't think it is worth the risk. I will do it with the wonderboard for anything do. or I won't do it. that is just me I guess
I wanted to ask a question within the question. what do you know about adding a biocide to the mortar? I am trying to remember a floor I did in a basement, directly on comcrete. We used that , No wonderboard though. Ever used this? Any thoughts ? anybody? Is It important under the wonderboard as well as the tile?"I was born in the country, razed in the city, I'm a natural born shaker from my hips to the ground"
Biocide... I think I used it on Aphids once...:-) No never heard of it.... seems that since the 80's there has probably been quantum leaps in adhesive chemistry that has reulted in some additive available for ceramic tile laid over concrete.
Good luck
RAlph
The best reason I can think of to use thinset to attach the backerboard along with screws is because the manufacturers require it. For the product to perform as designed, following the instructions closely can be pretty important. Also, some backerboard manufacturers offer pretty decent warranties- GP offers a lifetime guarantee on DensShield- but only if you install it according to their instructions. So you spend an extra $10 on a bag of thinset and a half hour mixing and spreading it around... seems like cheap insurance for a much stronger installation.
It results in a stiffer floor. Less flex, better long-term performance. I trowel it on with a notched trowel.