Hardibacker and DensShield tile backer

I'm taking a ceramic tile workshop and the teacher, who only claims to be a journeyman level tile setter, he is really a home remodeler turned schools system carpenter who also teaches in adult education.

for tile backer, he recommends
1) DensShield Tile Backer by Georgia Pacific and
2) Hardibacker 500 water resistant backer board

instead of cement board for a shower wall enclosure. I have never heard of these products but he was insistant that these were fantasic products and much easier to work with than cement board. Does anyone have any experience or opinions about these products?

He also said that generally no one puts up plastic or tar paper behind the tile backer board. Is that true is is he cutting corners?

thank you for your opinions,

 

He is right and worng about the moisture retarder. Since the facing on denshield is waterproof, then no vapor barrier is used behind it. If the backer is coated with a waterproofing membrane, then no vapor retarder is used behind it either. If no surface waterproofing is done to the backer, then a moisture retarder must be used. Backers will absorb water through the grout and vapor will leave the backer through the easiest way possible, which if it's not prevented from exiting the back by the moisture retarder, then it will evaporate into the stud cavities. You want it to come out through the grout. Often you won't find a requirement to use the moisture retarder in the instllation instructions of backer materials because even if the stud cavities got so rotted from moisture that the walls fell apart, the backer would have been unaffected by the water and therefor the product performed as designed because it did not degrade from the water. Hardibacker is my choice of backer. Never used denshield, just the fact that it is a gypsum core scares me away from it. When it first came out, there were specific requirements for waterproofing cut edges and fastener penatrations, and now they say using thinset is good enough. Thinset though, does not waterproof anything. Now did this instructor say mastic was OK in a shower or tub surround? I'd be getting my money back for the class if he did.

 

thanks for the information, anything sounds easier than cement board.

We haven't gotten to the info about mastic vs. thinset. We just destroyed what the last class created and did the wallboard and started putting the plywood on the floor. Next class Wednesday. We each get an area of 2-3 walls and a bit of floor per pair.

Matt, the instructor, said DensShield was probably only available at some tile stores, but the hardibacker is available at HD. He prefers Densshield for walls and hardibacker (1/4 inch) for floors (after putting on plywood).

 

How did he say to fasten the plywood and what kind did he say to use? Is this subfloor installation to joists, or underlayment plywood installed to the subfloor?

 

I should point out that Hardibacker is cement board...the filler is cellulous instead of sand..but the bonding agent in both is portland cement. Densheild, now that's another story.

 

Not sure if this adds anything, but we were going to have a tile place put up our tub surround and then tile. We were offered densshield as a backer. However, after reading many reviews, I found many unsatisfied customers using densshield. We ended up using cement board (Durock) and it was not that much harder to install than the greenboard that we used in other areas of the bathroom.

 

If this instructor (so-called) is going to teach such things then he should associate himself with a sanctioned discipline of the industry and know more about what he is teaching. He has room for much improvement fromwhat you've said so far.

He could begin with buying the "Handbook for Ceramic Tile Installation" from the TCNA (Tile Council of North America) and the related Specifications from ANSI (American National Standards Institute).

http://www.tileusa.com

Stay away from the Denshield my friend.
Stay here and we will have you knowing more than he does in about a week or less.