Walls and Ceilings - Corner mud cracked

A few months ago I was completely re-doing another room and was marvelling how good my mudding skills were getting. That being said, after my final coat dried, a fine crack developed for the entire corner on the exterior wall (where the wall meets the ceiling). I've read that this usually occurrs because of too much mud, but I really don't feel that I applied it too thick. I usually get good coverage, about 1/8". Could the temperature have caused this? It was quite cold out (first time mudding in winter) and the mud on the corners of that exterior wall took several days to dry. Could that have caused the cracking?

Long story short, I had friends coming to live with me unexpectedly, so I didn't have time to re-mud. I just threw a coat of primer on the walls so they could move in the following day. Now that they're gone, I've noticed the crack is not visible through the single coat of primer (even though I know it followed the entire length of the wall).

Should I mud that wall again? Or would I be safe just painting? I'm just wondering if that crack might re-appear in the future...

I was a service tech. for a large residential drywall company. I primarily serviced home owners with thier 12 week,and year end warrenties.

Corner cracks were always in the game plan. My main tool for repairing them was a thin bead of Duron MaxFlex caulk. Just run the length of the crack, and wipe it down with your finger........just like caulking trim.

Duron Maxflex was my favorate brand, it's easy to work and cleans up fast.....................and remains flexible for years.

Some service techs used drywall mud, but the cracks would return........I always caulked.

In these condos that were built around 1990, there are some terrible cracks in the corners on exterior walls. And in the garage they are so terrible that the paper tape looks not just cracked, but twisted. I'm sure that the 2 x 4's in these corners had a change in moisture content and really contorted from how they were nailed in, and the pressure was so great it tore the paper tape.

But none of this stuff ever bothers me. I don't consider anything like this catastophic or life or death. I will just caulk the interior cracks like the poster above suggested and touch up paint. But for the garage, it is beyond that. I'll remove the tape and do it again. (I've already done this to a nearby garage and the tape was easily removed.) Hopefully after all this time the 2 x 4's are not going to change much anymore. Then again...maybe out in the garage the temperarture and humidity swings are so great that this is just bound to happen. Good job security for me in my maintenance line of work. :)

You may want to see if the drywall was screwed in near the corner. Some drywallers let one side "float" into the corner, and only nail the adjacent board. when the building expands and contracts a crack can open up.

It happened in every exterior corner of my house. After I screwed both sides it didn't happen anymore.

Caulk can fill it, although I just put a new piece of tape over it and re-mud it. (cut out any wrinkles or torn tape first. You don't need to cut out the tape that is stuck well)

My .02

I've used the caulk and finger trick for years. The only thing I can add is sometimes I will chase the crack to make sure I get rid of any loose mud.

Wayne,

When you chased the crack, were you able to catch it? :)

Is chasing a crack a terminology?

It is for me. I'm not real sure where I picked it up, but IIRC it is a term for weld repairing cracks on pressure vessels. The crack is "chased" (enlarged) with a small grinder, "stopped" with a drilled hole and then repaired.
I sometimes use the pointy end of a church key (more terminology) to chase a drywall crack, but you gotta' be careful not to tear the tape.

Thanks for all the replies. Since I did the drywall, I know I screwed the corners.

I can no longer see the crack, so I think I'm going to try caulking it and see how that holds up over the years. Should I prime the caulk? or is it ok just to paint right over it?