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I am installing drywall in the new bathroom. The acrylic Tub/Shower unit is typical 30" x 60" with a 70" side wall (one piece). One side is installed against a 2x4 wall like this: flat end of 2x4 wall

On the end of this 2x4 wall, do I need to cut a 4-1/2" piece of drywall before putting on corner bead on the two corners? Or can I just install the corner bead onto the flat 2x4, and then mud between the two corner beads? Will joint compound adhere to the wood or do I need a piece of drywall there?

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  • Is there some reason you don't want to cover the framing with drywall, as is standard?
    – isherwood
    Apr 28, 2023 at 19:33

5 Answers 5

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Mud bonds to wood as well as it does to paper. I've done enough demolition to know this for a fact. The bead is the leveling mechanism, so finishing isn't affected in any way.

What the drywall would do is add stability--drywall doesn't tend to warp or crack with seasonal humidity fluctuations as wood might. That's the main reason such wall ends are normally covered along with the rest of the wall.

If you wish to reduce wall length by omitting the drywall, consider using a tougher setting-type compound that'll hold up better. Otherwise, drywall the entire wall.

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I am pretty far from a drywall expert (quite bad at it actually...) but you definitely need drywall on that end cap. You can probably get mud to stick to the wood, but it will be pretty hard to get to a good smooth surface for painting.

The alternative is to put some sort of more finished wood on the end. Essentially a 4.5" wide piece of molding/trim. If you get something exactly the right width then that will be easy. If you have to trim it yourself then you might as well use drywall, which is much easier to cut to size.

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  • I am guessing that the OP is thinking of needing to buy a extra sheet of drywall for 4.5 inches. The trim is a good idea.
    – crip659
    Apr 28, 2023 at 15:02
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    Trim is also more durable when things bump into it.
    – Ecnerwal
    Apr 28, 2023 at 17:43
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    Mud sticks to wood just fine, and a skim between beads is a skim between beads--it doesn't matter what's underneath. The knife doesn't know or care.
    – isherwood
    Apr 28, 2023 at 19:34
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Depending on the compound ... it might lose moisture into the wood and then not harden or not stick properly, or if it's thin (like, the thickness of a corner bead) the moisture might cause the wood grain to swell and show. There are ways around this but the easiest way is probably to use drywall.

You could just try it with your compound on a scrap piece of 2x4 from the same batch if you have one. You need to install the corner bead so that you can apply a single coat across the entire width, bead-to-bead, that isn't so thin that it will sink into the grain. IE the bead may need to be stood off a little.

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  • Wood isn't going to extract moisture more readily than paper and gypsum, and a bead is always stood off a little. That's why it's bead-shaped. :) This seems more like a guess than an answer.
    – isherwood
    Apr 28, 2023 at 19:35
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I applied mud directly to the wood between the drywall corner beads on a 2x4 wall in a closet door opening about 30 years ago. It was a fairly thin coat that I sanded smooth then painted over.

A little bit of the mud flaked off sometime in the first few years, I never bothered to repair the flaked bits, but the rest has held on quite nicely.

I see no evidence of the wood grain through the mud and have had very little issue with the mud flaking off despite the bi-fold closet doors being opened and closed multiple times a day over the decades.

So I'd say that "yes", not only can do this but that you can get good and lasting results from doing so. I cannot vouch for how this would hold up in the extra humid environment of a bathroom, though.

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There is another choice, a composite material typically used as exterior trim as it will never rot or decompose. It can be cut/sanded like wood, and won't shrink/warp/etc.

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