Had lots of shed doors on the farm that would freeze up in the winter due to design. Sorry you disagree, but I've seen it all too many times. It will freeze shut if the door is in a groove. Hell, the sliding doors on the shed I worked in all winter froze shut twice, and they aren't even in a groove. Snow blew under them, melted just a bit, and the froze. Spent a half an hour chipping the ice to get them open.
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