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Discussion Starter · #1 ·
When drywalling a bathroom above grade, is it OK to run the drywall (greenboard in this case) all the way down to the subfloor or should I leave a gap above where the CBU and tile will eventually be? The bottom of the wall will be covered by a base tile, so it would hide any gap, but I'm just wondering if it's necessary.

I've read here about the importance of leaving a gap when drywalling walls which meet a basement slab, to prevent moisture wicking up the drywall, but can't remember/find whether the same thing is recommended in a bathroom.

Thanks in advance.
 

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There's moisture in the bathroom. Leave a 1/2" gap above the tile floor to prevent wicking. The gap will be covered either by tile or molding.
Ron
 

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Mold!! Let's kill it!
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A gap is good. If you waterproof your tile backer (and you should), you could waterproof the seam between the floor and wall, which would do a really nice job of protecting your wall. If you haven't hung your drywall yet, use GP Densarmor. No paper=no mold. Greenboard is antique material.
 

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Discussion Starter · #6 ·
Greenboard is antique material.
Yeah, so I have come to learn from reading quite a few comments here. Unfortunately I bought the greenboard back in October and only afterward did I read that advice. :(

I'm not too worried. The room, a guest bath, is well vented and we'll put a good primer and paint on the greenboard, and leave the gap at the bottom like you suggest.

I was going to use Red Guard on the tile backer (Durock). So you're suggesting I put a little Red Guard on the cut edge at the bottom of the drywall, as well? Is that right?
 

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Mold!! Let's kill it!
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What I'm saying is if you are going to waterproof the Durock, then put the drywall down to the floor and waterproof it to the floor. Then no worries about wicking or water penetrating the walls.
 
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