Over the summer, we added crown molding throughout the house. After a couple months the crown split at every seem (in the middle of the walls not the corners). This happened in every room in the house, so I didn't think it's the house settling. It's about a half a mm gap between each piece now. I wrote it off as maybe the crown wasn't acclimated or the walls did some contracting or something with the winter cold.
Until yesterday, I noticed a new 4' crack running vertically through a wall. With plaster, I'd say nbd, but this is a sheet of drywall. I'd believe the drywall was probably hung 2 summers ago (before we moved in).
I can't imagine how enough force could be applied to a sheet of drywall to stretch it apart. I also would have assumed the screwholes would fail before the board split.
Anyone ever seem something like this?
Is the 4' crack running along the seam of two sheets of drywall?
If so, it wouldn't take much force to shear a piece of drywall tape, especially once a tear had been established. Wonky, twisted 2x material from a big box store is more common than straight, and it can behave erratically. It takes me a long time to pick decent 2x material from one of these places.
Crown separating from the ceiling is pretty normal, and there is a very good chance it was caused by seasonal movement.
Soft maple is what many high end paint-grade trim carpenters prefer, as the readily available poplar and especially pine are not as stable. Even when acclimated they can move depending on how they were milled and how straight of a section (knots, cupping, warping, twisting can be exaggerated by seasonal movement) they were to begin with.
But on the bright side, at least your copes/miters held! I'm guessing you used wood glue?