I had a cyc wall constructed. It is masonite and was built on a platform. Unfortunately it is splitting at the seams and getting worse with painting. I had someone come out and sand and mudd again but it didn't help. how do i salvage this wall?
Hard to say without pictures to judge. An overlay that has a bit of stretch to accommodate the substructure expanding and contacting and flexing. There's a spray some people use to hide small ceiling cracks, it's basically a latex rubber layer that will hold paint. You could lay sheet vinyl, my favorite solution, over the top, except complex curves like cove corners would be trouble. If it's a simple wall with curved bottom, and not an "el, however, that may work.