Replies

1. 
   davidmeiland | Dec 18, 2006 05:34pm | #1

   1/4" is fine on the floor. Does the radiant panel manufacturer approve using thinset to bond the CBU to the panel? I have looked into using Roth panels and apparently they do not approve this, so setting tile over the product is a challenge.

1. 
   billd60 | Dec 18, 2006 05:41pm | #2

   Good question.  This is my third tile job (all family) and my first over any radiant heat.  I'll check into it and let you know.

2. 
   billd60 | Dec 19, 2006 03:44pm | #6

   Stadler-Viega makes a product called Climate Panel - 1/2" thick and they fully endorse applying thin set and CBU directly to it.  I talked with their rep' yesterday. 

2. 
   FastEddie | Dec 18, 2006 05:51pm | #3

   What david said.  Also, you could use a membrane to reduce the thickness even more, but then we're only talking another 1/8".

   Try this article:

   September  2005  A New Way to Tile a Big Floor   A high-tech membrane minimizes the chances for cracked tile or grout failure Tom Meehan Tiling a big floor can be a big headache. If the floor below the tile moves, you may wind up with cracked grout lines or worse, cracked tile. Second-generation tile installer Tom Meehan starts with an uncoupling membrane made by the Schluter Company that allows the subfloor to move without affecting the tile. Tom also gives tips for laying out a big floor so that it looks best and minimizes waste. You'll also learn how to install an expansion joint, another key to the success of a big tile floor.

    

   "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

   
   

   ---

   Edited 12/18/2006 9:53 am ET by FastEddie

3. 
   user-158769 | Dec 19, 2006 07:17am | #4

   So long as your floor is fairly stiff, and with 3/4 T&G Advantech, it should be...1/4 inch CBU is fine. I generally use 1/4 inch wood underlayment followed with 1/4 inch Hardie Backer (3X5) sheets.  I also generally use a polymer modified thinset  (along with Durock screws) to bond the Hardie Backer to the underlayment.

   In your case, the routed  plywood panels will easily work as your underlayment and the 1/4 inch Hardie overtop should work well.

   As for membranes, you need a membrane if tiling a shower basin... and/or if you were tiling over a masonry floor that had cracks in it you definately need a membrane...but otherwise, I can't think why you would need one; unless the radiant tubing manufacturer is calling for one...such as a Ditra Schluter membrane (which is nothing more than dimpled plastic  coupled with a "slip" sheet on the bottom)...but I wouldn't  think this is necessary.

    

   Good luck on your project.

   Davo

1. 
   billd60 | Dec 19, 2006 03:41pm | #5

   Great info'.  Thank you.

2. 
   blue_eyed_devil | Dec 19, 2006 04:27pm | #7

   83004.5 in reply to 83004.1 

   So long as your floor is fairly stiff, and with 3/4 T&G Advantech, it should be...1/4 inch CBU is fine. I generally use 1/4 inch wood underlayment followed with 1/4 inch Hardie Backer (3X5) sheets.  I also generally use a polymer modified thinset  (along with Durock screws) to bond the Hardie Backer to the underlayment.

   In your case, the routed  plywood panels will easily work as your underlayment and the 1/4 inch Hardie overtop should work well.

   Davo, how could running two layers of underlayment be faster that tossing in some drypack?

   I don't understand the aversion to using real mud!

   blue 

1. 
   ClaysWorld | Dec 19, 2006 08:44pm | #9

   Sheet man that's the way we do it.

    

3. 
   FastEddie | Dec 19, 2006 05:52pm | #8

   Davo, the membrane takes the place of the hardiebacker. 

   "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