Trying to figure this out.

I am going to be using Hardibacker for wet areas around the tub-shower above the acrylic tub/shower surround, and drywall for the rest of the room.

There will be no tile.

The whole room will be painted.

What should I use for the gaps where the drywall and the Hardibacker meet?

Thank you for your time.

  • 1
    You don’t need hardibacker in those areas. Mold resistant drywall will suffice. If you insist, use a strip of wood to cover the gap between such dissimilar materials. You can paint it if you’d like.
    – paul
    Jul 29, 2018 at 23:27

2 Answers 2


If you are going to paint, the seams between the drywall and the hardibacker will need to be mudded and taped like any other wallboard seam or the joint will be visible and ugly. it will probably be hyper-visible actually, if you use glossy paint (as you should in moist areas).

I think you'll be fine with standard mud/tape, it's not a wet location, just moist if it is indeed above the splash zone (if it's not above the splash zone, you should use an alternate surface treatment instead of simply hardibacker). A good prime and gloss paint should protect the drywall, mud joint, and hardibacker.


What made you decide on Hardiebacker? If you used greenboard (drywall with a water-resistant front side, e.g., here), it would merge with the regular drywall much more cleanly. Otherwise, I would think there's going to be a very visible difference between the two areas, as Hardiebacker and drywall have different textures. Even after you paint, you're going to be able to see the transition between the mud and the Hardiebacker, which is not going to be a straight line.

  • Some or all Hardiebacker is less than 1/2" thick. I have seen one instance where use a shim material was tacked on the edges of the studs to make up the difference. The material looked to me like perforated Masonite fiber board. In this case the transition between Hardiebacker and drywall was obscured by tile so there was no visible transition between the two. Jul 29, 2018 at 20:31
  • It's not the difference in thickness that worries me: no matter what you do, you're going to have to tape and mud and you can cover any thickness change that way. It's the difference in texture: the drywall and Hardiebacker panels when painted are going to look different and feel different.
    – Paul Price
    Jul 29, 2018 at 20:36

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