Glue Down Durock? Do I Have To?

Originally Posted by Bill_Vincent

Floordude-- I agree with Jerry. Are you sure it's the 18 volt? A friend of mine bought the 14 voilt from HD, and that thing won't hold a charge for even an hour of constant use. My 18 will go atleast a couple of hours, and by that time, the second battery is fully charged.



This is why I leave people shaking their heads sometimes. When deciding who I should listen to, there are three sources I check. First, is the manufacturer's instructions. Second, is TCNA recommendations, and third is my own field experience. There are many times where I don't agree with a manufacturer about their own product, and this is one of them. Another good example would be Schluter saying you can go over sheetrock with Kerdi. But in the case of the fiberock, that void still exists, and for that reason, I'll listen to TCNA's recommendations. Who knows-- they might be right, and for some reason, thinset isn't needed. I'm not about to put my reputation on the line to find out, though.

Originally Posted by PrecisionFloors

My thoughts are, what happens to the "sweat" on the other side.

Originally Posted by Bill_Vincent

That's exactly my thought. I know it won't do anything immediately, or even with in 5-6 years. But over time, I'm afraid that the condensation will deteriorate the gypsum in the sheetrock, and make it rot. I'm not about to find out the hard way.

Originally Posted by Jerry T

Bill, I love ya like a brother and I am not being argumentative... it's more like butting heads here . The sole point I was attempting to get across is that Fiberock is not a "CBU" backer board. It's a backer board for sure, but it is classified as a "Fiber-Reinforced Water restistant Gypsum backer Board Underlayment" type of backer board.

Hardi, on the other hand, is classified as a "Fiber-Cement Underlayment" type of backer board. To make this more confusing, James C Hardi claims hardibacker falls under both the "Cementitous Backer Unit (CBU) type of backer board along with the "Fiber-Cement" type of backer board.

This article explains the differences in backer boards far better than I can...
http://www.tileletter.com/Sept06/TCNAtileBackers.htm

But forget all that and I will use jerry speak to make this point .

Say one of us was hired to go to install tile over CBU backer board... if I put down Fiberock , I would be using a product that was not within those specifications. This maybe a small issue but it has the potential to be a huge issue. Imbedding it in thinset is a whole nother issue... and USG is the one saying we don't need it, not me. That's one of many reasons I don't use Fiberock.

I check in on several tile forums and i have noted many times posters saying.... "I use Fiberock CBU under my tile jobs". Can you see my point?

Just trying to get all installers to know what they are putting down before they do it.

Originally Posted by Michaeljp86

This is how I would have done it because thats how I read to do it. I feel less stupid now .

Originally Posted by 415moto

Where did you read that a CBU mnfctr say to use adhesive?