Ok so me and my dad build a sliding barn door for one of the doors for our garage. But the wood is like curved outward in the middle. Does anyone know or have any ideas on how to make it straight? Would nailing some 2x4s on the back going to pull the bottom of it back out? Or should we just get new pieces of plywood. We are planning to do some white trim on thefront side to make it look pretty, probably azak or something. Thanks for any help.