grout crumbling


  #1  
Old 09-28-02, 07:13 AM
MikeMoz
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grout crumbling

I replaced the floor in my bathroom with 12" ceramic tiles. A few days after grouting the tiles I noticed that a 4 " section of one grout line did not set properly and started to crumble. I removed the grout and regrouted the area which again crumbled. I again removed the grout and regrouted. The line is starting to crumble again. The tile is on backerboard with the joints filled with thinset and fiberglass tape. I can't feel any weakness in the floor below the joint. The rest of the floor grout lines are fine. Can someone give me some assistance.
 
  #2  
Old 09-28-02, 02:12 PM
Join Date: Nov 2000
Location: Austin, TX
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You have movement! Use sanded colored caulking that matches your grout and use it in the grout line and honor it as an expansion joint!!!

Really!!!
 
  #3  
Old 09-28-02, 02:50 PM
A
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Hi
Sounds like you didn't set the concrete board in thin set...it stops the movement you just mentioned. If the tile is loose maybe you can take it out and add a few nails to the spot that is moving, and replace the tile.
 
  #4  
Old 09-29-02, 05:16 PM
finnigan
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thinsetting the concrete board

Canada are you suggesting that the cement board should be fastened down to the wood floor with thinset? Or thinset on the cement board under tile?
 
  #5  
Old 09-29-02, 05:31 PM
MikeMoz
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Hi

Thanks for your responses. I did not set the backerboard with thinset but I did screw it to the underfloor with screws following the pattern on the board, about one screw every 8 ". I guess this was not enough. I will try the colored caulk if can find it.

Thaks again
 
  #6  
Old 09-29-02, 06:08 PM
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OH, OK...

I see the problem now. I assumed you knew how to install the cement board!!!

Here is the installation specs for hari-backer cement tile board.

Cut and paste it without the tags on the ends(if it has them), to your browser. They quit letting us post hyperlinks here, because someone abused it.

www.hardibacker.com/hardibackerinstall.htm
 
  #7  
Old 09-30-02, 05:59 PM
A
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Hi
Yes, all cement board manufacturers say that their board MUST be set in thin set before it is fastened to the subfloor with either nails or screws. Backerboard is pretty useless stuff if you don't do this. It's not used to glue the board to the floor..only to fill the voids under the board an prevent it from moving.
 
 

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