Helps on Cement Boards meet the extsting celling

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Old 11-11-12, 09:55 PM
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Helps on Cement Boards meet the extsting celling

Greeting,

I have cement boards installed on all 3 walls above a bathtub. The cement boards are all the way up to the ceiling. I want to keep the existing ceiling and will have Redgard apply to the vertical cement board only.

I need install mesh at the corner where cement boards meet ceiling.What should I do to the existing ceiling? Can I apply thin set, regular drywall compound or apply Regard?

Thank you.
 
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Old 11-12-12, 03:37 AM
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I am assuming you will be tiling to the ceiling. If you use a mesh at the top, and it isn't 100% necessary at that level, offset the majority of it on the vertical cbu and just let it hang over the ceiling slightly. IMO, I would not lose sleep over that small space. Your tile will butt up to the ceiling, eliminating that crack totally, and the chance of water ever finding its way up there is remote.
 
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Old 11-12-12, 06:43 AM
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Mesh tape and thinset all cement board to cement board joints and inside corners. Leave ceiling pristine and tile up to the sheetrock on the ceiling and apply a bead of color matching caulk. You will have to tape and mud the areas where the cement board meets sheetrock on the verticle walls but the ceiling joint in not needed. Personally, in your case, I think the Redgard is a not needed. I assume you have a moisture barrier behind the cement board.
 
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Old 11-12-12, 04:57 PM
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RE: Helps on Cement Boards meet the extsting celling Read more: http://www.doit

Here is my problem:

When I removed the vertical walls, the ceiling edge that meets the walls are damaged, not smooth anymore. I can not caulk. BTW, there is no tile on ceiling and I will not install tiles on ceiling either.

I really don't want to replace the ceiling. How do I fix the damaged ceiling edge?



Thank you for helps.
 
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Old 11-12-12, 05:34 PM
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If you were a little agressive on the tear out and damaged the ceiling. Install you cement board up to your ceiling. Tape the corner and feather it out in both directions. What the original intent assumed was that you had a clean line across the ceiling. Don't sweat it, we have all been there.
 
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Old 11-13-12, 05:06 AM
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You might not need to tape the ceiling. The cement board comes out 1/2" and I think tile does the same or close. If that takes care of the gap all you need to do is touch up the ceiling with joint compound. If not, I'd do as czizzi suggested except instead of folding the tape and taping the corner like you normally would - just flat tape the ceiling.
 
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Old 11-16-12, 06:38 PM
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RE: Helps on Cement Boards meet the extsting celling

Hi Pros,

Got some questions for caulking the corners where vertical walls meet ceiling. I will install tiles all the way up to ceiling.

1) After installing the cement boards, should I apply caulking around the corner where the vertical walls meet the ceiling?

2) After installing the tiles, should I apply 2nd caulking around the corner where the tiles meet the ceiling?

Thank you.
 
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Old 11-17-12, 04:38 AM
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There shouldn't be any need to caulk the cement board but you should caulk the tile to the ceiling after the grout has dried.
 
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Old 11-17-12, 08:55 PM
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Got it. Thank you marksr.
 
 

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