My husband bought the osb several years ago for a project that never happened, and has just been in my garage taking up much needed space. I told him his window of opportunity was now closed! I had about 6 sheets of it, so that helped with the cost. It does have to be painted, which I will get to on Tuesday. It is much cheaper than plywood but I don't think you can let it be exposed to the weather very long without paint. I have some left over and I am going to use it for my nest boxes, too. I can't wait till Tuesday to work on my coop some more!