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so we just drywalled all walls in our bedroom. And now (~ 3 weeks later) one of the joints is cracking in the middle edge of the tape.

Summary:

  • The house is concrete. Built 1970s.
  • All drywall boards are glued onto mostly concrete walls (some of the lighter interior walls are made of very dense chipboard)
  • All joints are taped, then spackled / mudded three coats, then sanded.
  • Primer / sealer is applied.

The crack is in a joint where there's concrete walls behind.

It's more significant closer to the ceiling (that section is pictured below). And becomes less pronounces towards the floor. It stretches over about 1,5 meters.

Here's an image of the crack.

enter image description here

Do we apply new tape over the old one now. Or do we wait a year, let it settle and crack some more, then fix it?

EDIT: Thanks for all your replies so far.

EDIT 2: It turns out the crack took place in the edge of the tape, not in the center as stated before.

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    That looks like shrink to me. Was the main taping coat completely dry, and pure white, before you continued? If not, you'll just need to skim it again and prime and paint.
    – isherwood
    Jun 3, 2018 at 21:44
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    What kind of mud did you use (I have had issues with fast-set mud when used on hot days)? What kind of tape did you use (the mesh tape, in my experience, is a crack waiting to happen)?
    – Jimmy Fix-it
    Jun 4, 2018 at 1:25
  • @isherwood The taping coat was definitely dry before continuing with the next coat. For most coats we waited 20-24 hours. However, for some taping coats we put a thin layer on top of the tape, while laying down the tape. Because we noticed the edges of the tape would attach more strongly to the mud if the edges were a bit wet. I'm still not sure what gives the best result. Completely dry tape, or a thin layer.
    – Håvard Geithus
    Jun 4, 2018 at 9:07
  • @JimmyFix-it We used paper tape which had tiny tiny spikes on one side. We put that side on the mud. We used slow setting mud (on the package it said ~ 5 hrs, but we waited 20-24 hours). The mud we used is called 'light spackle mud' and is what most people use in Norway.
    – Håvard Geithus
    Jun 4, 2018 at 9:09
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    Since it is a old enough home that the settling should be done (many years ago) I would rework that area now no need to wait. I would remove the cracked area tape, I usually do have mud on both sides when taping but a thin coat two much will cause cracking and in some cases there is no way to stop all the cracking with tape. I have had good success on concrete / block walls using a paper like sheetrock paper on top and skim coating/ spray texturing over that but even that will crack of the temp swings are two large. With crack prone walls I will use panneling very 70' S but it works.
    – Ed Beal
    Jun 4, 2018 at 11:45

3 Answers 3

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Cracks like that occur because of, 1) settlement, or 2) expansion/contraction.

1) If the House was built in 1970’s, then it has finished settling. Unless there is some underground work in the area, like new utilities, new piling, etc.

2) I suspect it’s expansion/contraction due to the joint compound being too wet.

There is no need to “wait for it to settle and crack more”. I’d redo it as Jimmy Fix-it has suggested.

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  • I'm thinking we scrape off / dig into the cracked part to remove loose bits. Then mud and tape again. Make it a really wide joint on top of the old one. What do you think?
    – Håvard Geithus
    Jun 4, 2018 at 9:16
  • So this is what I ended up doing. I used a 'wallpaper cutting knife' and cut in behind the tape to get it off. After removed for the cracked area, I sanded down using crude sandpaper (60 or 80) to give some room for the new tape. I made sure there were no loose bits in the area. Then vacuumed and used a dry microfiber cloth to brush away any particles. Then put another tape coat on there. Took about 30 minutes.
    – Håvard Geithus
    Jun 4, 2018 at 22:32
  • Please consider making the answer self-containing for future visitors :)
    – Håvard Geithus
    Jun 4, 2018 at 22:44
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If the concrete you are talking about are cinder blocks, then they are notorious for cracking like that. Usually over time they do stop cracking and then I do a repair. So if in fact they are cinder blocks, I would wait a year or so and then deal with it.

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  • Thanks for your answer. The underlying concrete is just concrete, and very solid and dry. Almost 50 years old.
    – Håvard Geithus
    Jun 4, 2018 at 9:15
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"one of the joints is cracking "

So, only one joint has cracked.

If the underlying problem is that the joint compound was too wet, then one would expect cracking at at least some of the other joints mudded from the same batch or container. One could apply similar reasoning regarding other 'systemic' causes, such as not enough drying time between layers, type of compound, etc. Of course these issues could be present in a minor way variously, and they all happen to be taking place at this one joint.

Those issues as pointed by others deserve consideration as possible causes, I'm not saying that any are not the cause, but my 2-cents differ.

It could be (and looks like it to me) that the two adjoining sheets are not well adhered cement wall at that joint, for any of various reasons. If this is the case, (1) cut out all of the loose area, call this the 'hole', (2) cut a patch that covers a bit larger than the hole, (3) hold the patch up over the hole, draw it's outline on the wall, (4) put the patch aside and enlarge the hole to the outline of the patch, (5) remedy the cement surface as necessary, (6) adhere the patch in place, (7) bevel the edges of the hole and patch, (8) mud and tape as before.

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  • The plaster boards are really well adhered to the cement wall as we used a really strong, high quality glue for that (similar to Tec7). And the that particular concrete wall is about 50 cm thick from the 1970s. It seems very unlikely.
    – Håvard Geithus
    Jun 4, 2018 at 22:42

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