wall separated from floor?

If you are seeing a gap like that there is a structure issue not just the plywood . If it is metal sided you have wood framing. Chances are the floor framing is rotted or at the least warped down. Most manufacturers of wood framed walls use elevator bolts to anchor the walls to the floor not just screws. These bolts have large surfaces to support the load and do not pull through. Be ready for some bad news sorry to say. I would start looking for a replacement