Butting Hardiebacker to drywall [Archive] - Ceramic Tile Advice Forums - John Bridge Ceramic Tile


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02-07-2010, 08:16 AM
I'm redoing the tile in a 7' by 5' room with just a toilet and a tub/shower. I've removed the old wallboard that was under the tile around the tub, to a height of 54" above the top of the tub. My wife and I think we'd prefer to take the tile higher than it was, taking it above the shower arm but not all the way to the ceiling. (We both think the tile would be a bit too much if we took it all the way up, given the size of the room.)

I've put blocking between the studs so I can screw down the Hardiebacker edges, but I've been assuming it would be all right to run my top row of 13" porcelain tile on the existing wallboard with the seam between the Hardiebacker and the wall board buried under the tile.

Would I be better off using Hardiebacker to the exact height I want to take the tile to and then deal with any cosmetic/transition issues above the tile?

And am I correct in assuming that I should use thinset and not drywall mud in the seam between the two materials?

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02-07-2010, 08:42 AM
You can stop the Hardibacker at the height of the shower head, and continue the tiles onto the drywall. Yes, tape and mud the joint like any other backerboard joint, with CBU tape and thinset.

You are planning some sort of waterproofing for this wall, right?

02-07-2010, 08:45 AM
Yes, I'll be putting up some 4 mil plastic before putting the Hardiebacker up.

Thanks for the quick reply!

02-07-2010, 09:10 AM
John, I would suggest using a surface applied water proofing material, either a paint on or a fabric instead of the plastic behind the the BB. Although the plastic behind the BB is an approved method. In my opinion it is just easier than dealing with the caulking of the plastic at the tub flange. Hammy

02-07-2010, 09:32 AM
I'm down to the studs, so I was assuming my choices were felt or plastic. Is there something else that would work? Is felt easier to work with than the plastic?

02-07-2010, 09:45 AM
No, plastic is about as easy as it gets.

Do consider Hammy's suggestion. Having the waterproofing on the surface of the backerboard makes your shower dry out quicker, reducing the potential for mold.

02-07-2010, 12:04 PM
Aha! (That's the sound of a light bulb popping on -- maybe.) So the suggestion is to put up the Hardiebacker, then use paint-on waterproofing before tiling? I could do this instead of plastic under the backer board? Or in addition to plastic?

02-07-2010, 12:51 PM

Don'tcha love those 'Ah-ha!" moments? :D

02-07-2010, 03:30 PM
John, if you're transitioning to 1/2" drywall, you might want to consider something besides Hardibacker. For me, the downside of Hardi is the fact that it is just slightly less than 1/2", making a little speed bump where it meets 1/2" drywall. You can get around this by sistering the stud at the transition, bringing the sister out a tiny bit to eliminate the bump.

Alternately, Durock and Wonderboard are right at 1/2" and make better transitions.

02-07-2010, 04:27 PM

02-07-2010, 04:53 PM
Yep, that one, too.