Cement Backer Board? [Archive] - Ceramic Tile Advice Forums - John Bridge Ceramic Tile

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mpatheal
09-07-2001, 03:53 PM
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

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John Bridge
09-07-2001, 04:03 PM
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.

Rob Z
09-07-2001, 05:56 PM
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
09-07-2001, 07:08 PM
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
09-07-2001, 08:33 PM
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

Rob Z
09-07-2001, 09:39 PM
Hi Jason

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

Jason_Butler
09-07-2001, 09:45 PM
See ya there !!!

mpatheal
09-08-2001, 07:25 PM
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.

Rob Z
09-08-2001, 08:37 PM
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
09-09-2001, 09:36 PM
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

Rob Z
09-09-2001, 09:44 PM
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
09-09-2001, 09:50 PM
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
09-09-2001, 09:54 PM
check this out

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

Rob Z
09-09-2001, 09:58 PM
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
09-09-2001, 10:07 PM
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

Bri
09-09-2001, 10:10 PM
You can get it at Home Depot in Canada...but it's way too expensive there...try a tile shop...

Rob Z
09-09-2001, 10:22 PM
Mark

I think DAL Tile carries it. They do up here in VA.

Rob

John Bridge
09-10-2001, 05:45 AM
Mark,

Hate to admit this, but I don't know where Marshall, TX is.

WallyPoP
09-10-2001, 06:07 AM
I'm getting a bit nervous. It appears that most times CBU's are mentioned, I see the names DUROCK, WonderBoard, Hardibacker, etc., but almost never DensShield.

I just started a project installing DenShield 1/2" on walls and 1/4" on bathroom floors, after I did a batch of reading on the aforementioned products. DensShield appealed to me BECAUSE Georgia-Pacific claimed and supported via test results all the good things you get from DUROCK, etc PLUS, lighter handling, score and snap like sheetrock and vaporbarrier built in. The exposed side is suitable either for mastic or thin-set.

Please, someone advise me now before I tile re the apparent/implied negativism toward this G-P product. To me, a tyro, (I've done just 4 installations to date, using DUROCK) the advantageous od DensShield to a DIYer seem outstanding.

Hope it's ok for a non-expert to interject his obviously less qualified, limited experience, opinion.

mpatheal
09-10-2001, 06:29 AM
Hey John,
Marshall, Texas is in the Northeast part of the state, on I-20, 25 miles East of Longview, and 35 miles West of Shreveport, La., the hometown of George Foreman, Y.A. Tittle, and Bill Moyers.

Rob Z
09-10-2001, 02:50 PM
Wally

You get the JohnBridge Vocab award for the day. I had to go look up "tyro".

All the mfr's of all tile setting products make the various claims, supported by various tests.

The advantage Denshield has over some of the others is the waterproof coating on the surface. As long as the seams and the edges are sealed with silicone, you end up with a pretty water tight installation. The fasteners have punctured the surface, but at least there are very few places where a fastener lines up directly with a grout joint.

The siliconized gypsum core supposedly won't degrade with expsoure to water. I just experimented with a piece of Denshield and left it out in the rain for a month on some saw horses. The piece of Denshield laid on some plastic sitting on a piece of plywood, and this way sat in a puddle of water every time it rained. The piece of Denshield was still intact, with very, very little degradation of the integrity of the piece.

If you followed directions and set the tile properly, with good grout and caulk, I think you will be okay.

I personally have never used it on floors, only on counters, backsplashes and tub surrounds.

Don't stress about it now.

Rob

John Bridge
09-10-2001, 04:43 PM
Mark,

I looked Marshall up today. Found it up by Longview. It's a guy in Longview who's accused me of faking the "Mt. Houston" dilemma. Can you imagine?

Wally,

What's done is done. But I have stated all over the Internet that Denshield is a waste of time and money. I've even called it garbage. My two cents.

mpatheal
09-10-2001, 10:41 PM
Rob,
I checked out the level of the floor today (using your method) and found that I had a crown of about 1/4" to 3/8" over a span of 8' in one direction, and little or no difference in the other direction. By the way, I am checking this in a bathroom about 7' x 12'. I am also tiling a kitchen/dining area about 15 1/2' x 19'. I have not completed tearing out the particle board in that room yet, but based upon the surface of the existing linoleum, I think the room should be within your tolerances. Let me know your thoughts.

Hey John, we here in Marshall don't cotton to those longview folks either. But you'll have to bring me up to date on the "Mt. Houston" dilemma.

I am going to let you guys debate the dens-shield issue. From what I have heard so far, I think I'll try the Hardibacker.

Mark

John Bridge
09-11-2001, 05:47 AM
I just can't believe there's anybody left in Texas who isn't aware of the rape of Mt. Houston. There's a link in the bottom left corner of every main page of this site.

http://www.johnbridge.com