Taping sheetrock behind tiles?

Old 05-03-14, 11:58 AM
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Taping sheetrock behind tiles?

I am going to replace the tiles in a shower stall. I am assuming that I can't remove the tiles without removing the drywall behind it.

Should I use cement boards for the wall? And if so, do I need to tape the seems?
Old 05-03-14, 12:54 PM
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Those are pretty basic questions for what is a major job. Are you sure you are up to doing it?

You need to have a water barrier behind the cement backer board, or you need to waterproof the backer board using something like Redgard. If you use the Schluter-KERDI system you can use regular sheetrock as a substrate.

Yes, all joints need to be taped withe the appropriate tape and compound for the material used. You don't use sheetrock tape and joint compound on cement backer board.
Old 05-03-14, 12:57 PM
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I'm not a mason or tile guy. Just speaking from experience.

Use the cement board behind the tile.

My parents had a shower stall installed by a "friend" years ago. He used standard sheetrock and some water resistant rock. Needless to say.... neither lasted as the wall collapsed from water penetration.

I installed cement board and used fiberglass tape and thinset mortar to seal the seams. I did the backer board but subbed out the tile work.
Old 05-04-14, 07:12 AM
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Thanks. How about taping transitions?
1.) from cement board to shower pan - just live a small gap between board and pan?
2.) cement board to drywall? Use the same mesh as for cement board?
Old 05-04-14, 07:52 AM
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No tape needed at the shower base. Bring the cement board down to the lip and then extend the tile over that to within 1/8" of the base and finish with flexible color match caulk that blend the gap into the grout.

Plan your cement board to drywall transition so that the final course of tile or bullnose overlaps the actual transition which is then found just beneath the final tile. Leaves a smooth wall transition to tile that you also run a bead of caulk. I treat this transition with mesh tape and setting type drywall compound (20 min mud). Very important that there is sufficient wall studs beneath this section so that both the cement board and the drywall is supported on both sides of the transition. Less important across the horizontal plane, but critical along the vertical seam between the two surfaces.

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