Cement Backer Board?

[mpatheal]

I am getting ready to lay ceramic tile in a pier and beam house, and about to purchase CBU. Can any of you pro's give me your thoughts on the best CBU. I've heard of Hardi-board, duorrock (spelling?), Wonderboard, Dens-shield, etc. Is there any difference? Your opinions are appreciated. My sub-floor consists of 1x8's on a 45 degree angle to the floor joist, soon to be removed particle board - replaced with exterior grade plywood. Also, if I am laying the CBU on thin-set, do I still need to screw or nail the board down.
Thanks, Mark

[John Bridge]

Welcome aboard, Mark.

There'll be some people here shortly to tell you everything you'll ever want or need to know about cement backer boards.

Hi Mark

Could you tell us what the joist size, spacing, and span is?

I'm glad you are getting rid of the particle board. it's bad news.

Spend some time reading the posts from "particle board over 2x6 T&G floor".

This will give us some basis to start from.

I'll check back in later.

Rob

[LDavis]

Yes, you still have to nail/screw the CBU to the plywood even with the thinset bed beneath. I prefer nailing on floors, its just quicker for me. The vast majority of my CBU experience is with the hardibacker product, primarily 1/4" on floors. In my experience, this product is easier to handle, cut, and doesn't leave little "cement crumblies" around when you score/snap. Be sure to follow all maunfacturing installation recommendations and this product will perform well.

I know of many other tile setters that prefer the cement boards like wonderboard and durock. Point is, they all will, have, and do perform the same job. Get some other opinions, make your choice, and follow the respective instructions. It will do the job, which ever one you choose.

BTW, answer Rob's question about floor support, IE joist size, centers, etc.

[Jason_Butler]

Hi Guys,

I have used the hardibacker as well with no major complaint - except for the dust when cutting.

The latest issue with hardibacker I'm facing in Austin, TX ius availabilty. I was in three different Home Depot stores today and none of them are stocking the 1/4" board. They still have the 1/2"

Maybe it's contract renewal time and HD found a better deal. The product of the week at most HD's is RHINO BOARD. Ever hear of it? Rhino Board and Wonderboard were the only products available in 1/4"

Jason

Hi Jason

Let's move discussion about product problems over to the hangout.

[Jason_Butler]

See ya there !!!

[mpatheal]

Hey guys, thanks for the info on the CBU. Rob, sorry so long in getting back to you on the joist info. Been ripping up particle board all day. Whew!!! The joists are 2x8 on 24" centers, with a 7' span between beams.

Hi Mark

Good man! Tearing out the particle board! Just say NO to particle board.

The 2 x 8's spanning 7 feet is good. The 24" centers is not good.

I would recommend overlaying the 1 x 8's with T&G 3/4" plywood to start. What are the transitions like to other flooring in the house? How much elevation do you have to work with?

Rob

[mpatheal]

Hey Rob, I was afraid you were not going to like the 24" centers on the joists. I am a little ahead of you on the 3/4" t&g plywood. I have already layed that in the bathroom. Still have the kitchen/dining area to go. As far as the transitions go, in the bathroom, after the 3/4" t&g, were still 1/2" below the hallway, and will be the same after laying it in the kithen/dining area. What are you thinking?
Mark

Hi Mark

Assuming the 3/4T&G plywood makes it seem nice and beefy...I would either go with Ditra or 1/4" cement board. After putting down a zillion sheets of cement board, I am really starting to like the Ditra. It costs a bit more, but it goes down faster and saves wear and tear on the body.

Ditra also offers some advantages over cement board other than ease of installation.

Is the floor flat enough to set tile on?

Rob

[mpatheal]

Rob,
The floor seems level enough, no noticable bulges or depressions. Should I check it with a level?
Tell me more about ditra. Is this another type of cement board? Where do you get it?
Thanks, Mark

[Bri]

check this out

http://www.schluter.com/english/products/h6.1-ditra.htm

Mark

For what it's worth, Brian and I are Ditra converts. Some of the other guys aren't as impressed with it. Both Ditra and cement board, when properly installed over a good subfloor, will give a good substrate for tile.

As for the level...can you get a really straight piece of 1 x 4? Maybe 8' long. use that to check for crowns and dips in the floor, and try to measure what you see.

For example, a crown 1/8" high over 8' won't be a problem. A crown 1/2" over 4' will be a problem.

Let us know what you see.

Rob

[mpatheal]

Thanks guys,
Rob, I will check the levelness (is this a word?) tomorrow and get back to you.
Bri, thanks for the link, this stuff looks impressive. I haven't seen this at Home Depot or Lowes. Is there someplace in Texas you can get this?

All you guys are great. I really appreciate all the help and feedback
Mark