Help with shower tub.

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  #41  
Old 06-17-09, 07:47 AM
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HeresJohnny,
Question: Since we know that moisture will travel through the final mud bed to the liner, If you use the final mud bed to lock in the CB don't you run the possibility that moisture in the final mud bed may wick into the CB?
JoeP
 
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  #42  
Old 06-17-09, 08:03 AM
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Joe

Yes. The cement board will wick some moisture, however it will not hurt the cement board. If the pan is draining properly, this wicking should be minimal though. Additionally, the vapor barrier behind the cement board should divert any moisture that gets behind the board back inside the pan liner. Interesting that you ask this question. There are some pros that are of the opinion that the cement board should not be buried in the deck mud as the cement board can wick moisture.
 
  #43  
Old 06-17-09, 08:15 AM
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I should follow this up by saying that you can install the cement board so that the bottom is 1/4" or so above the final mud bed. This will eliminate any wicking issues, however you have the last 6" or so of cement board "flapping in the breeze". The thinking here is that the cement board and tile will be rigid enough to hold up for the bottom 6" or so. Some do it this way, but I dont.

Edit: Official TCNA manual states to keep cement board "out of mortar bed/caulk bottom edge". So there you have it.
 

Last edited by HeresJohnny; 06-17-09 at 09:00 AM.
  #44  
Old 06-17-09, 08:20 AM
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It is my intention to avoid complete rip out. There is a reason the tile looks nice.........it's EXPENSIVE.

Anyway, the repair is now postponed until at least June 29th, due to complications on both sides (my schedule and the other person's).

I intend to use the advice received here as a guide, as well as this document which pretty much says the same thing.

http://www.oatey.com/shower_drains/l...an%20Liner.pdf
 
  #45  
Old 06-29-09, 04:32 PM
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OK, so the repairs began today.

Demolished the floor and halfway up the wall.

Found.....

No preslope as Johnny suspected. Also found that the outer edges were actually low spots, and that's how the water stayed there....in fact....the drain was about 1/4 inch higher than the edges.

Found the weep holes were clogged.

Found the leak was from water permeating the grout lines, and finding its way thru a gap in the cement board (in the corner).

The fix will be:

redo the pan as described (preslope already laid in).....will add spacers on top of weep holes, too.

redo the bottom half of the wall, and make sure the corner doesn't have a gap......(open to suggestions on best method to seal a joint between two sheets of cement board)......I was thinking cut a strip of membrane and glue it into the corner using thinset or maybe an adhesive of some kind....

reinstall the tile.

seal the crap out of everything, especially the grout.
 
  #46  
Old 06-30-09, 10:02 AM
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redo the bottom half of the wall, and make sure the corner doesn't have a gap......(open to suggestions on best method to seal a joint between two sheets of cement board)......I was thinking cut a strip of membrane and glue it into the corner using thinset or maybe an adhesive of some kind....
The corners and all cement board joints should be taped and mudded with thinset. Make sure you use the alkalai resistant tape made specifically for this.

From your response, it sounds like you may be under the impression that cement board is waterproof. It is not. While it is unaffected by water, water will pass through it. Kinda like a puddle on a concrete slab.
 
  #47  
Old 06-30-09, 06:14 PM
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Thanks Johnny......that is exactly what was done for the corners......and I understand that NOTHING is waterproof, just water resistant.

By the way the new membrane now goes up the wall just about 14 inches.
 
  #48  
Old 07-01-09, 07:26 AM
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Most important, is to make sure you have a preslope under the pan, use pea gravel (or something else) around the weepholes and install blocking between the studs to fully support the pan liner.
 
  #49  
Old 07-01-09, 03:49 PM
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It all done except for grouting, and we used tile spacers over the weepholes.
 
  #50  
Old 07-02-09, 05:46 AM
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Sounds like a better job the second time around.
 
  #51  
Old 07-03-09, 02:03 PM
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One can only hope.

Anyway, the job is now completed. I am going to let everything sit over the weekend so the grout and the caulking have a chance to completely set, and we'll see what happens when we use the shower again.

Thanks to everyone who helped. Using the advice here I was able to talk things out with my friend who really went out of his way to make things right for me. It did cost me some money for materials, but he ate all the labor which was 3+ days.
 
  #52  
Old 07-03-09, 02:42 PM
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seal the crap out of everything, especially the grout.
One last step before you are done done! Good luck!
 
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