We've hung and finished drywall in about 80% of our home in the last few years. Until now, we haven't had a single crack at a joint.

We're doing our living room right now, and we've got three very thin cracks at three of the butt joints. We did everything the same as in the previous rooms.

We noticed them after the previous pass of mud, and thought maybe it was because of the temperature. (Long shot, but our windows are being refinished, so the room is a little cold and drafty. It's about 62 degrees in the room.) I warmed the room up, put plastic over the windows and we put on the last pass of mud. That was two hours ago, and the hairline cracks have already shown.

My lady does the mudding. She said she didn't "V" out the butt joints before putting up the tape and mud. Just forgot, and when she remembered it was too late, so she just rolled the dice. She's convinced this is the cause. I believe her, but we thought we'd ask, before we proceed.

Most importantly, wondering what recommended solution is.

Thanks.

 

Give a push on the area around the cracks and see if the drywall moves any. Cracks sometimes are from drywall screws that "spun out" before they truely sank into the stud. This results in the drywall not being fully driven home and floating slightly over the stud. Add screws or drive a couple of drywall nails to pull the sheet tight before re-mudding.

 

Thanks, but I wish.

The drywall is very solid. Was the first thing I checked.

 

What is the joint compound and type of tape you are using?

 

Sheetrock brand joint compound, and mesh tape.

I know people will suggest using paper. And others suggest mesh.

Either way, like I said, we've hung and finished over 70 sheets of drywall and never had a crack.

 

Gonna suggest that in this case, it is the mesh tape with a little push from the cold temperatures. I will preface by saying, that I use almost exclusive mesh tape - but I also use exclusively a setting type compound. Setting type compounds dry by chemical reaction and form a harder surface. Regular joint compounds dry by evaporation and are not nearly as strong. So for these particular sheets of drywall, there is some lateral movement that is causing the hairline cracks.

 

Paper tape is stronger than the mesh but I don't think you'd seeing cracking right away from the type of tape.

EDIT: Never mind, Z got in ahead of me with a different opinion.

 

These are forming so fast I have a hard time believing its because the drywall is moving, but I'm not an expert.

Any solutions? She took one of the seams apart, cleared the mud and removed the tape, so she can "V" the joint.

Open to any less invasive suggestions.

 

Hold off until you can get conditioned space again. Simple expansion and contraction from heat differentials is enough to cause movement. Not only in walls, but flooring as well.

 

I agree the cold [maybe damp] temperatures were part of the problem. The only surefire way to prevent cracks with sticky tape [mesh] is to cover it with a setting compound.

 

I wonder too if maybe the joints could have been prefilled with a setting compound before the tape. Any joints wide enough to hold mud usually will turn out better if you prefill them. Otherwise those sheets have a gap where all the movement becomes focused.

 

Until I learned better and started using setting mud I had this problem sometimes on butt joints. Yes, prefill if the gap is more than 1/16" And sometimes I think the mesh tape gets frayed right overs joint if one piece is a little higher than the other and tape that is frayed in the middle of the strip is as good as no tape at all.

 

She removed the tape, made the "V" at the joint and remudded.

That was a week ago, no cracks.