I'm designing a new 8x8 coop and don't want to break the bank. Plywood is $40 a sheet and OSB is only $10 a sheet...$360 difference when I count up the walls, floor, and roof. My wallet would much prefer to use OSB but I wonder how well it would hold up long term. It rains here most of the time (Willamette Valley, Oregon). What kind of success or failure have you guys had with OSB in outdoor uses? How long could I reasonably expect it to last once painted?