Looking for advise how to approach tiling a kitchen backsplash about 18 square feet. The wall is a prengineered wall, a Warsaw home type. Interior wall is a rigid paper based board. Issue is there is a verticle crack in the wall 10 inches from where the right side of tile backsplash is to end. Crack is 1/8 open in winter and closed tight in Summer. The crack is where two wall panels meet. I had filled the vertcle crack with drywall joint compound to smooth out the wall. The two panels move just that 1/8 inch every year. Can I just tile over this crack without a backer board? the wall surface is dry wall like material that is a pressed paper material. Please let me know ideas or thoughts for my tile project. Thanks!