I have a 28 year old bi-level. In the stairway on the lower part of the stairs t the wall below the steps there is a gap between the side of the steps and the drywall. Also outside of the coat closet at the top of the stairs there are bad cracks on the corners on the outside of the closet at the steps. I have checked under the steps and there is no sign of the concrete floor cracking or sinking. The steps themselves are level. As you can see in the pictures the trim around the top of the steps has dropped. However there are no cracks at oint where the closet wall and he ceiling meet. Any ideas on what the cause could be? Note the pictures posted turned to the left except the first one.