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Bathroom drywall -- gap needed at bottom?

6K views 6 replies 4 participants last post by  Maintenance 6 
#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.
 
#2 ·
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
 
#5 ·
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.
 
#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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