Cracks forming between wall and ceiling

What is the width of the cracks

All are 1mm and one is 2mm.

Do you have trusses?

It sounds like typical truss lift. Here is some information:

Interesting article. This does sound like what I am seeing. I haven't gone into the attic yet. I did peek in last winter and it looked ok up there. At least from what I can tell that is. It's interesting that the article talks about installing crown molding. I have been thinking of doing that actually. I may now have a good reason for my wife ;)

Thanks,

Use a very good quality Latex caulk to seal it , it will expand and contract , you will need to redo it.

The trusses will still lift. If you are going to do crown, you should look into pinning it to the ceiling rather than the wall, I think I remember Journal of Light Construction doing an article back when.

If it becomes a major issue, the best solution is to not nail the drywall to the trusses for about 2 feet at the interior wall. Carry the drywall with clips or nailers on the top plate so that the trusses can lift without arching the drywall at the wall ceiling intersection. This will be a mess to accomplish without disturbing an existing ceiling.

Yeah, the article mentions that the crown should be nailed/attached to the ceiling. Also, that they should be painted in the winter so that when they do move, a paint line will not be exposed.

It's funny how the article mentions that this is usally only a concern by new home owners as I am one of those (going on my 2nd winter).

Thanks again for the advice. I was worried for a bit but it's good to know that this is probably not a structural problem with the house.

information:

Interesting article, though I'm not sure I agree with his moisture differential stuff. I always thought it was due to the fact that the diagonal webs are restraining the bottom chords in such a way that as they shrink the bottom goes up (unlike a second floor joist which can shrink but not lift--basically the whole works comes down as it dries). It does also seem plausible that thermal expansion/contraction could be a factor. If this is the case, then ventilation is not going to help. It would be worse in new houses that got very wet during construction, but also, could be simply seasonal wood movement (driest in the winter in a cold climate in a heated house).

Knock your lights out: