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Is it considered acceptable in drywall / sheetrock work to use caulk to finish an interior corner instead of using tape with joint compound?

This is not my own DIY idea – this was suggested to me by a drywall contractor.

In this specific instance it was a wall-to-ceiling corner which is about 26' long.

My sense of things is that this would be a shortcut, and if caulking was a high quality substitute for taping then no one would ever use tape. I'm pretty sure caulk would be more prone to cracking over time, especially since caulk shrinks and the joint would have no reinforcement.

But there could certainly be methods and/or products I'm not familiar with!

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  • 4
    I have never heard of a drywall guy using caulk in a corner. Caulk is expensive compared to mud and tape, I like to use pretaped corners they cost a bit more than tape but look awesome. Corners are cheaper than a quality caulk.
    – Ed Beal
    Mar 6 '19 at 20:11
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    Is there something about this particular corner that calls for alternative solutions? I suspect that there's more to the story.
    – isherwood
    Mar 6 '19 at 20:23
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    @isherwood that's a fair question but I don't think there is anything special... the ceiling does follow the roof slope so the angle is > 90. its about 10' up. That's all I can think of. Mar 6 '19 at 20:42
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    Oh, that explains it. Your taper wants to use his hand-dandy corner trowel. Tell him to bend it.
    – isherwood
    Mar 6 '19 at 20:47
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    @isherwood I see - you mean that he's not confident to tape a non-90 degree corner without that tool. got it, thanks Mar 7 '19 at 12:16
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First I would not even have a conversation with that contractor. Gone instantly. If he is cutting corners here, what else would he do without you knowing? Bye.

Caulk in corners - I have had to do this as a temporary fix but here are your issues:

  • your corner isn't really a corner. Corners look good because of the sharp angle. You can for sure see if a corner has been caulked and it looks off to the eye. If you don't care about aesthetics then no big deal.
  • paint does not adhere to caulk like it does drywall/mud. No matter if you use the most paintable caulk in the world, the caulked part will look off. Paint will chip, paint will be more easily discolored, and touching up painted caulk will look lumpy.
  • caulk will not last unless the home environment is both well conditioned and very stable. So you might get away with caulking an inside wall on the first story of a two story house with a basement that is always set to 68F. Might last you 7-10 years if you don't touch it. Doing a wall on a ranch in a temperate climate, the drywall will shrink and expand, make the best caulk pull or get brittle within a year or two and you will have to constantly have to recaulk. Simply not a long-term solution.

But the fact that this topic was breached with a home owner is a huge red flag. No normal contractor that does drywall would even have this thought in their head.

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    Cutting corners... I see what you did.
    – JPhi1618
    Mar 6 '19 at 21:09
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    @JPhi1618 - I am glad someone caught the pun.
    – DMoore
    Mar 7 '19 at 1:25
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    Find a capable drywall guy that knows about Strait-Flex P90. (If it isn't clear, the "drywall contractor" you found wasn't actually one.) Mar 7 '19 at 3:37
  • I once used spackle to repair a really bad corner, to the point of having to reshape a good 2 feet of it. It is fiddly, hard to get the sides both straight at the same time. It is also prone to "sagging" so you need to stretch the job over a few days with sanding in between. It is not especially fun, and had I known then how big a job it was I would have cut half a foot of each drywall, install new on each side and done the corner with a premade tape corner and the joints with straight tape. And that was spackle. Caulk, not at all. Mar 7 '19 at 11:50
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No. Caulk might look great for a short time (if it doesn't shrink to oblivion right away), but it doesn't bond to the cut end of the gypsum panel at all. Eventually it'll crack loose.

You need tape in most cases to create a solid bond (tape-on-paper, essentially), and to add structure and continuity to the joint.

That said, I have used caulk to repair poorly-taped corners, just as an aesthetic tool.

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    Having a 26' long joint done well enough that caulk only would be acceptable would be a feat in itself.
    – JPhi1618
    Mar 6 '19 at 19:29
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I’ve used a high quality no shrink paintable caulk when I’ve made a very clean cut drywall edge both on an inside wall to wall and a wall to stipled textured ceiling. I finger tooled and it not only looks great, it saved a ton of time and finesse and continues to look great. I fully understand the drywall purists position but take a good look at all the new products that have entered the market in the past few years you may be surprised

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Apparently there are some caulks which are actually made for this specific purpose. I doubt any standard "painter's caulk" would work well, but this is worth bearing in mind if you are in a market where this is available.

The specific example I just saw was from Germany - the product "KNAUF Power Elast" which I spotted in a video. Presumably there are alternative similar products.

enter image description here

I don't read German but from a translation it seems like this material is meant to be particularly elastic which makes sense to avoid cracks. I can see where, if this worked well, it could be a lot easier than taping a corner (especially for a non-pro). It is also paintable.

There are some other interesting differences between the German practices for installing gypsum board and what I'm familiar with in the US. (No joint tape anywhere, for one thing, just mud).

When installing the caulk, these were my observations:

  • Used only for inside corners

  • Some type of watery joint prep (primer?) was painted on prior to caulking

  • Caulk was applied with a normal caulk gun & then finger tooled smooth

Anyway, no doubt the specific instance posed by the question was not good practice, but its good to be aware their might be valid alternatives in some places.

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In a tiled shower yes, the corners are usually caulked rather than grouted like the joints; but drywall? no, it is a bad idea.

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My parents house the inside corners were caulked instead of being taped by the drywall contractor and the corners are still perfect now 20 years later! And I have personally done it in my house 5 years ago on some remodeling and it still is perfect as well. So no it is a great idea I love it. So much easier to do.

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  • Do you happen to know what kind of caulk was used? Was there any joint prep (like primer) or just baredrywall? Jun 29 '20 at 17:47
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Caulking can absolutely be used. But this is not black and white. There are conditions to be met. If the joint is large, no way. You can absolutely fill a Corner with 45 or 90, sand it, and caulk the corner with high-quality flexible caulking. Tooled PROPERLY, you will never know the difference and it won't crack for a long, long time, if ever. Smear it all over the walls and yeah, you'll see it like night and day. Also as some have pointed out it depends on your location, mostly to do with humidity levels. It doesn't have to be x degrees always , that's silly. It just has to be a humidity level consistent with the type of caulking you used and how much of it you used, as well as how you tooled it, what type of paint you used , etc. Paper or hybrid plastic/metal tapes/corners are always superior, as they are designed for the application, and are more closely related material-wise to the products they're being applied to. like any product, more work +specialization leads to a better result. Think 2-in-one shampoo. Gets the job done, looks great, but you can't beat Shampoo and conditioner and the extra time put in for great hair. See the pattern here? It always amazes me how many yes or no answers come from these questions, from would-be professionals, when the only answer you'll get from an actual professional is : "It depends".

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  • Some of these "would-be professionals" have been building houses for 20 years. Care to share your background? Maybe you've got the same experience, maybe you're "a guy on the internet" - we don't know. Have you done what you've advised and had it last for 10+ years? Please edit your post and add that experience, it will go a long way toward supporting your answer. Also, a few line breaks for readability would be nice. I do like your shampoo analogy, excellent point!
    – FreeMan
    Sep 28 at 11:40

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