New Drywall Installation - Hairline Cracks

Greetings.

New to the forum. I’d be grateful for any input.

The problem is cracked drywall joints, walls and ceilings, in a basement renovation. I’ve read around the forums and spoken with a few experienced friends, but can’t decide on the cause.

I started with an empty basement in a 20 year old house on concrete slab. Basement is half below grade. Walls are 9’ high, wood studs on 16”, ½” drywall vertically. Ceilings are 2x10 joists on 16”. 12.5’ span. ½” drywall right on the joists, long seams perpendicular to the joists. Mesh tape and low-dust compound throughout. Paper-lined metal corners. An HVAC/plumbing bulkhead runs the length of the room.

Most of the mudding/taping was done over a year ago, then the project sat. I finished up the mud about a month ago. I installed electrical, primed, baseboards, tile/carpet, and was about to paint when the cracks started opening.

The first one ran up from a door frame. Rookie mistake, I butted a sheet of drywall against the door frame. Figuring that was what caused it, I sanded out the entire joint, and redid it with paper tape and setting compound. That’s held for a few weeks.

Now most of the joints have cracked. None of the butt joints, only the long, machined joints. None go below 4’ on the walls, but all go right to the ceiling. Ceiling cracks are wall-to-wall. They ‘seem’ to be making their way around the room in the order that I did the mudding / taping.

I’ve got a few partial theories, but I’m hoping for some more experienced input on my situation before I start repairs...

Thanks for reading. Many thanks for input. Endless gratitude if you come and deal with it for me.

 

The only time I have seen drywall joint compound crack is when too much was applied in one pass. It is generally accepted that a minimum of three layers of "mud" be used with each layer allowed to dry/harden thoroughly before applying the next layer.

 

Would have been better if you had of used all paper tape and 5/8 on the ceilings.
Sure you used enough screws?

 

@ Furd: Do you see that type of crack develop as long as a year after mudding? I did 3 (sometimes 4) coats. Being my first good sized job, I was moving pretty slowly. Each layer had at least a few days to dry. That's plenty long, no?

@ Joe: Agreed on the 5/8". It somehow escaped me when I bought the sheets. There is some movement between joists. Only slight, though.

Also agreed on the paper tape. I've since learned how mesh tape can be a problem when not properly set. But a friend of mine has done many basements with mesh and dustless without issue. His good luck, perhaps?

Screws were done every 10" on the walls, every 6" on the ceilings. The walls are solid. No movement at all when pressed on.

I appreciate the responses...

 

I would blame it on the mesh tape rather than paper tape and the low dust compound. Did you use low dust for everything? When using mesh tape, "setting compound" is best for bedding the tape. IMO that's 100% of the problem.

IMO the low dust should be used only for the final coats that will get sanded.

Butt joints above corners of doors will often crack, even with paper tape and setting compound. You want to span door headers with the drywall, not end the drywall at the upper corner of a door.

Walls partially cracked could be a moisture issue behind the wall, with high humidity. But more than likely its that the lower part of the wall stays a cool and consistent temperature, while the upper part and ceiling expands and contracts more.

 

I'm a DIYer so I can't say I have seen miles and miles of drywall joints. I detest working with drywall but I have never had cracks develop when I use thin coats of mud and paper tape. I personally would never use more than a 1/8 inch layer at a time. I don't know how thick you spread it so I don't know why yours cracked. I only know what has worked for me in the past. I posted that about thick mud because the first time I did a mud job I did lay it on too thick and it did crack.

 

I agree it's likely the mesh tape that is the big issue

The cracks from mud being applied too thick are random - kind of like a clay pit that has dried out with cracks going every which way. If the cracks are from the tape - it will be more or less in a straight line. I've seen mesh tape wait a yr or two before it started to fail. While 5'8" drywall is always better on the ceiling, the fact that you have joists on 16" centers should make 1/2" drywall acceptable.

 

The mesh tape is your problem. If you insist on using it you must use it with a hot mud for the first layer.

Paper tape is always better.

 

One more vote for the mesh tape being the issue - I thought of mesh tape as potentially the reason before I read your question far enough to see that you had actually used it.

 

Great. Thanks for the input, folks! Easy to say now, but I also blamed the mesh. I was stumped by my friend's good track record with it, so I needed more convincing.

Now starts the awful repair. I'll sand everything out and replace with paper, and probably setting mud. Over-kill, perhaps, but I don't want to be back here in another year!

Thanks again. You all do great things for a lot of people. Cheers.