My house is ten years old,I have arched opening leading from the family room into the kitchen. When they were putting the wall up I noticed that the wall started to sink. The workers went downstairs into the basement and put a 2x4 perpendicular on a support beam running parallel with the wooden I joist. I wasn't to confident with that so I added some floor jacks for added support. The problem is a crack appears in the drywall every year because of movement and I was wondering what was the best way to fix this?