Using backer board to raise tile up?

Reply

  #1  
Old 10-31-06, 10:42 AM
Member
Thread Starter
Join Date: Sep 2005
Posts: 9
Received 0 Votes on 0 Posts
Using backer board to raise tile up?

I am installing 9/16" hardwood flooring, and then doing ceramic tile in my kitchen.

The tile I bought is only 1/4" thick.
Can I use concrete backer board on top of my concrete slab in order to bring the height of the tile closer to the height of my hardwood?

I would like a nice even seams between the two surfaces.
http://static.flickr.com/105/276441089_78b8336fcc.jpg

Also, I currently have Linoleum flooring in the kitchen. It is very thin about 1/16"

I have read D Taylor's sticky on the subject, but I wonder if it is ok to apply backer board over the Linoleum. It seems logical to me as you normally use the concrete boards over a wood floor.
 
Sponsored Links
  #2  
Old 10-31-06, 11:41 AM
kchinth's Avatar
Member
Join Date: Feb 2006
Location: Chicago
Posts: 223
Received 0 Votes on 0 Posts
1. Installing concrete underlayment board over concrete tends not to be recommended.

2. If you read the sticky, there is no reason to ask the question...

"Can I put backerboard or underlayment over my linoleum or vinyl and install tile over it?".

Again, the answer is no. You have not dealt with the compressive nature of these products and this effect will be transferred through the backerboard to the tile, resulting in failure due to cracking.
 
  #3  
Old 10-31-06, 12:02 PM
Member
Join Date: Oct 2006
Location: Freeport
Posts: 60
Received 0 Votes on 0 Posts
I've installed Ditra uncoupling membrane which is 1/8" thick with approximately 1/16" setting bed between slab and Ditra. Then thinset the tile with unmodified thinset as per manufacturer specs. The edge at the wood can be finished with a "schiene" to complete everything. Go to Schluter.com to check out products. Also I think your tile might be a little thicker than 1/4"
 
  #4  
Old 10-31-06, 01:29 PM
Member
Join Date: Jan 2006
Location: USA
Posts: 3,505
Received 4 Votes on 4 Posts
You cant put cbu over a slab. Tile Pro's suggestion of ditra and then tile should put you pretty close to the 9/16" your looking for. Thinset, ditra, thinset, tile should do it. Remove the Lino.
 
  #5  
Old 01-21-07, 02:04 PM
Member
Join Date: Jan 2007
Posts: 1
Received 0 Votes on 0 Posts
durock over concrete

We plan to put tile around a basement bar area which will flow to an area of carpet. Can you use concrete board to raise the tile closer to the level of the carpet? Thanks
 
  #6  
Old 01-22-07, 01:42 PM
Member
Join Date: Jan 2006
Location: USA
Posts: 3,505
Received 4 Votes on 4 Posts
No cement board over concrete slab. What is the total height your are looking for for the tile to be the same height as the carpet. If both are going over the slab you shouldnt be that far off. There are transitions you can use for minor height differences.
 
  #7  
Old 01-22-07, 10:55 PM
Member
Join Date: Nov 2006
Location: USA
Posts: 1,342
Received 0 Votes on 0 Posts
Two things, 1) I've carpeted lots of areas like this and the tile is normally much lower than the carpet and the tile edge is not sufficient surface to stuff to and have it stay there so I use "Z" bar to hold it down. 2) This is not the first time I've heard not to use concrete board to raise tile level on a concrete slab. Will some one please explain why? I've never done it myself, but have carpeted many the slab floor where it was done and have never heard later that there were issues with it.
 
  #8  
Old 01-23-07, 07:11 AM
Member
Join Date: Jan 2006
Location: USA
Posts: 3,505
Received 4 Votes on 4 Posts
Smokey

Cement board needs to be mechanically fastened as you know. The thinset under cement board is there to fill any voids that may exist between a subfloor and the board. Take a look at the data sheets, install instructions etc of the various cement boards. None tell you they can be used over a concrete slab. Trying to bond the cement board to the slab without mechanical fasteners will be problematic as movement will eventually break the bond and likely cause tile failure. Im not sure what type fasteners you could use to mechanically bond cbu to a slab that would sit flush with the surface of the cbu. Carpet over the cbu on a slab I would think would be less of an issue than tile.
 
  #9  
Old 01-23-07, 10:41 AM
Member
Join Date: Nov 2006
Location: USA
Posts: 1,342
Received 0 Votes on 0 Posts
ALL RIGHT! I smell another discussion coming up and another chance to learn. I was taught, many moons ago, that the fasteners were just there to keep pressure on the thinset under the cbu to cause it to ooz around and fill in all the voids and do it's job. That's why I use roofing nails instead of screws. The nails have a big head and will do a better job of this than screws since the screw heads can break through the surface more easily and then the tension on the thinset is lost. Because the purpose of the concrete board is to compensate for the expansion and contraction differences between wood and tile, the thinset is eventually going to break loose from the wood under the board, just as the uncoupling membrane does, and the tile will be adhered to the board, but the board won't be to the wood floor. Once the thinset is set up, the fasteners are no longer needed, but are too much hassle to remove and there's really no point in doing that. Tile, glued to concrete, doesn't tend to break loose because the two materials have the same expansion and contraction rate. Concrete board is a much more rigid material than Ditra membrane. This stuff is made to uncouple and, when it does, appears to me to be a less strong or stiff surface than concrete board. Tile, glued to a slab, doesn't come loose unless it was improperly done. Consequently, why would concrete board do so? Do the instructions specifically address this or, due to it not being mentioned, is it a general assumption that it isn't a good idea? Do you have any experience where this has been done and was a problem later?
 
  #10  
Old 01-23-07, 02:21 PM
Member
Join Date: Jan 2006
Location: USA
Posts: 3,505
Received 4 Votes on 4 Posts
Smokey

All right so lets discuss it. Nails and screws are necessary for cbu way after the thinset sets up. They hold the cbu to the subfloor permanantly. That is their purpose. Thinset fills the voids, nails and screws secure the cbu to the subfloor. Do some searchs on other sites as well, dont just take my word for it. But Ill say it again no cbu over a concrete slab. Custom Building Products (wonderboard) makes no mention of being able to use wonderboard over a slab. All their literature addresses installs over plywood and osb. James Hardi does the same for hardibacker. These are the two I work with most but Im sure durock and others are the same. They need to be mechanically fastened and held in place and thats not happening over a concrete slab. Draw whatever conclusions you wish from that but as I said check out some other forums.
 
  #11  
Old 01-23-07, 04:01 PM
Member
Join Date: Nov 2006
Location: USA
Posts: 1,342
Received 0 Votes on 0 Posts
These folks who make no mention, I just want to be sure what's being said here. Is it just that, no mention, or do they say not to do it? If they say not to do it, do they say why? If they say nothing at all, where did the "don't do it" thing come from? You're not the only one who's said this, so there has to be a reason for it. I just don't see the logic in it. If gluing concrete board to a slab is an issue, why is it an issue? What detrimental effect does it have and have you seen any of those effects? Thin set is very effective in adhering tile to concrete, so I would think it would do the same with concrete board since they expand and contract the same. Hardi I can see an issue with due to the layered construction of it. Without the fasteners, I'd think the layers might possibly come apart, but concrete board doesn't have that issue. I'm not really interested in drawing conclusions unless there's no definitive answer, I'd just as soon learn something. What other forums might have info on this? This is pretty much the only one I use.
 
  #12  
Old 01-23-07, 04:32 PM
Member
Join Date: Jan 2006
Location: USA
Posts: 3,505
Received 4 Votes on 4 Posts
Smokey

Read the links on wonderboard and hardi. They dont mention install procedures on a slab, because they are not to be installed on a slab.

http://www.custombuildingproducts.com/docs/data_sheets/1-4%20WonderBoard%20DS.pdf?user=arc&lang=en

http://www.jameshardie.com/pdf/backer-install-new.pdf

Read your private messages.
 
  #13  
Old 01-24-07, 12:35 PM
Member
Join Date: Nov 2006
Location: USA
Posts: 1,342
Received 0 Votes on 0 Posts
Hey HeresJohhny, This is what I have so far. Neither of the links you provided said any thing about this, so I went to Customs site and sent an e-mail asking about it and am waiting for a reply. In the mean time, CTIOS's field report 83-12-2 (R-96) Says this about it - PROTECT YOUR LIABILITY

"Field experience has taught this author to remind you of tips on how to stay out of trouble. These tips include: backer board installed over concrete slab does not serve as anti-fracture resistance, concrete slab cracks will transfer through the backer board unless some form of slip sheet or membrane is used between the concrete slab and the backer board, each backer board manufacturer is responsible to include the fire rating of the backer board (this may include fire rating vertically and/or horizontally), and taping of joints is mandatory. When the installation of the backer board is installed by another trade, you are required to field inspect for minimum Industry Standards including taping of joints, correct expansion joints, correct waterproof membranes or weather resistive barrier papers, V8 inch in 10 feet for horizontal installation and V8 inch in 8 feet for vertical installation. Your liability is exposed unless you inspect and reject all conditions not in conformance. This includes verifying the correct fasteners were used at correct spacing."

It isn't saying not to do it, it's saying not to expect it to act as an anti- fracture membrane which any experienced installer knows. The way this is worded leads me to believe the author of this report does recognize installing concrete board on a slab, else why would he say, "backer board installed over concrete slab" and then go on to explain how to accomplish the anti fracture feature in this instance? I'm still looking for something in writing from the powers that be that definitively says, don't do this and here's why. I'll keep you posted on what I get from Customs, if they respond.
 
  #14  
Old 01-24-07, 01:09 PM
Member
Join Date: Oct 2006
Location: Freeport
Posts: 60
Received 0 Votes on 0 Posts
Try this link at James Hardie. It's a question & answer area. They spell it out do not use on concrete slab. Also can use dry set or modified thinset.
http://www.jameshardie.com/backerboard/homeowner/faq.php#5
 
  #15  
Old 01-24-07, 01:53 PM
Member
Join Date: Jan 2006
Location: USA
Posts: 3,505
Received 4 Votes on 4 Posts
Smokey

You need to mechanically fasten backerboards. I still dont know how you propose to do that. If you read the info I sent you to, I cant imagine how you can draw the conclustion that you can install cement board over a concrete slab. All the literature talks about fasteners. Theres a reason for that. Why do you suppose that none of the board manufacturers have instructions on how to install over a concrete slab. When you check with Custom Id be curious to know if they will honor their warranty on wonderboard installed over a cement slab. All I can say is if you want to use cbu over a concrete slab go ahead and do it. I'll not advise anyone on this board to do it cause I know its wrong.
 
  #16  
Old 01-24-07, 01:55 PM
Member
Join Date: Nov 2006
Location: USA
Posts: 1,342
Received 0 Votes on 0 Posts
Tile Pro, I went to the site you listed and this was all I found there.

Q: What subfloor should Hardiebacker be installed over?
A: The minimum subfloor specified is 5/8" exterior grade plywood or 23/32" exterior grade OSB subflooring. Hardiebacker board must be installed in accordance with local building codes and the floor must be engineered not to exceed the L/360 deflection criteria, including live and dead design loads, for the specific joist spacing used. Hardiebacker is not designed for use over concrete.

I can understand not doing this with Hardi due to the layered construction of the material. The fasteners help hold it together and, if glued to concrete slab, it could come apart. This, of course, is just a guess on my part, but comes from past experience with this product. Concrete board, however, does not have this type construction so it shouldn't be an issue. Are you aware of anything from Wonderboard or Durock saying not to do it and if so, do they say why? I'm not much with computers and, so far, have not met with much success finding this information.
 
  #17  
Old 01-24-07, 02:01 PM
Member
Join Date: Jan 2006
Location: USA
Posts: 3,505
Received 4 Votes on 4 Posts
I would pose the opposite question. Have you found anything from wonderboard and durock that says that you can?
 
  #18  
Old 01-24-07, 02:09 PM
Member
Join Date: Nov 2006
Location: USA
Posts: 1,342
Received 0 Votes on 0 Posts
HeresJohhny, I'm not questioning your competence as an installer or your knowledge of the field. You're not the only one who takes this position. I've heard the same thing from other very competent installers so, at face value, it would seem to be the case. It just doesn't make sense to me so I'd like to know why this is the case and, so far, have seen nothing to convince me it actually is the case. I've done flooring a long time and am convinced the most incompetent installers are the ones who never work to increase their knowledge base. Part of that base needs to include the "why" of it all or it's tough to convince a customer they have to spend this extra money or can't do this thing they want to do. "because I said so" pretty much never flies with my customers, they want to know why. Consequently, since I've seen this done by others and have never seen issues from it, I'd like to know why it shouldn't be done or why anyone knows it's wrong. As I said earlier, I'll let you know what Customs has to say if I don't find anything before hand.
 
  #19  
Old 01-25-07, 09:35 PM
Member
Join Date: Nov 2006
Location: USA
Posts: 1,342
Received 0 Votes on 0 Posts
OK, I got an answer from Customs The answer came from K. J. who is part of their Technical Service Department. This is what he said.


( It’s not an installation we warranty, because the installation of Wonderboard (WB) requires the use of screws to attach it to the floor in addition to the thinset.



BUT……I have done what you’re doing and it does work great. It is just very important to make sure you have an adequate amount of thinset on the floor so as to achieve complete contact to the back of the WB. Once each piece of WB is set into the thinset you need to weigh it down with something, such as stacks of tile or bags of thinset, anything that will hold the board flat until the thinset cures hard. (overnight)



K. J. CTC, Technical Service Representative )

I don't know about the rest of you, but I'm ready to put this one to bed. Thanks to all who participated for a great discussion. It's been a lot of fun, I've learned something, and, hopefully, we've helped out a few DIYers.
 

Last edited by Smokey49; 01-26-07 at 08:41 AM.
  #20  
Old 01-27-07, 07:50 AM
Join Date: Nov 2002
Location: Canton Ohio
Posts: 1,397
Received 0 Votes on 0 Posts
Reselect products of similar thickness.
 

Last edited by Daniel Wachtel; 01-27-07 at 08:01 AM.
  #21  
Old 01-28-07, 05:45 AM
Member
Join Date: Oct 2004
Location: New Jersey
Posts: 1,132
Received 0 Votes on 0 Posts
This is kind of an absurd discussion. No cbu's on a slab. Part of the process is the screws that pull the cbu into the thinset. Not only is each screw pulling the board down to ensure coverage across the entire underside, it's also removing all the air from under the backer in the process ensuring complete support.

As to the email from cbp tech support, the first thing they said was no warranty. The second part was he stacks boxes of tile ontop of the cbu. So for arguments sake, You have a 60 sf bath floor. Thats what, 5-7 boxes of tile? That's not enough tile to fully weigh down each sheet anyway. I sure won't buy 30 extra boxes of tile to weigh down the 4 sheets of cbu. So what's next? take a chair maybe and throw a couple boxes on that? Sure, will give you a heavy point load on the 4 legs providing they don't rock, but it won't uniformly compress anything. What then, place a piece of plywood under the chair? That would only spread the load creating a pretty small psi, certainly a negligible amount as compared to fasteners driven through plywood every 8".

These companies are out to make money. If they can come up with a method or accepted use of their product, they will.

For the bar area, Just tapcon some 1x2's to the floor in the area to receive tile, prime with you slc primer and pour your slc. Make the box the size you would need to maybe not have to cut any tiles as well. Measure the tile (tile sizes are usually nominal sized) and grout joint for you calculations. Box the area, measure diagonally corner to corner to ensure it's square. Complete your project and start drinking at your bar.
 
  #22  
Old 01-28-07, 06:46 AM
mattison's Avatar
Member
Join Date: Mar 2003
Location: Cinti, OH
Posts: 5,549
Received 0 Votes on 0 Posts
Maybe I missed it hidden within all the discussion on how to use board but did the op's question ever get answered ??
 
  #23  
Old 01-28-07, 06:53 AM
Member
Join Date: Oct 2004
Location: New Jersey
Posts: 1,132
Received 0 Votes on 0 Posts
Sure did. Th op's question was answered in a series in posts in the first 3 replies. The piggybaccked thread was answered as well. No problems here. Lots of seemingly sidetracked discussion though to try to educate as to the why's. Sometimes when a post shows misleading information or suggestions that fly in the face of manufacturer and industry suggestions, the debate is needed to keep the op from figuring they might be fine to follow the easyway out misguided advise. Very important for them to understand the "why".
 
  #24  
Old 01-28-07, 06:59 AM
mattison's Avatar
Member
Join Date: Mar 2003
Location: Cinti, OH
Posts: 5,549
Received 0 Votes on 0 Posts
Cool thanks.
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: