it would be painted of course. but i'm wondering if it would be sufficient for the walls. (actually it would be covered not with paint, but with a solid color stain, which is better than paint)
OSB is not meant to be an exterior product. If you cover it in another material (siding), you'll get more life out of it. Otherwise, continued exposure to weather degrades the integrity of the OSB and the glue will loosen, the wafers will separate, and the sheets will begin to break down. Heavy coats of paint might help to slow the process, as the paint would act as a moisture barrier (the stain may keep the color better, but will it prevent water from getting into the OSB?).
It won't last as well as plywood, and I wouldn't do it myself, but if you are in a not too excessively wet climate and can build sufficient roof overhangs to keep the worst of the weather off the OSB, you have a reasonable chance of getting maybe 5 years out of it if unpainted, a bit more if you paint. I would not rely on stain to take the place of paint, in this instance, btw. You want something that fills all the bazillions of little holes and crevices and voids, and creates a very solid waterPROOF layer. Also, stain (or more accurately, tinted sealer, which is the only sensible alternative to paint in this case) has to be redone every year or two, so that over time the cost will get to be as high or higher than paint, and the labor greater. Personally I'd just use plywood - which doesn't cost THAT more, requires less paint, and will last much longer. But I guess I could see using OSB if it's only meant to be a short-term structure and/or if you have a source of very cheap or free OSB but not a source of similarly cheap/free plywood. Good luck, have fun, Pat
Our current plan is to use OSB, covered with tarpaper, covered with pallet wood siding for the walls of our coop. DH likes the affordability of OSB, I like a happy hubby, and, I am determined that all my labor put into the pallet reclamation project not be in vain! In our mild climate a single uninsulated wall seems to be advised. We'll paint the OSB and studs on the inside with a good coat of something glossy and waterproof. Thanks to whoever started this thread, it seems to confirm our plans.
