I have an untreated barn wood door that I've had as my computer desk for a few years since I've salvaged it from the interior of a barn. I love how it looks but we are changing things up in the office and there isn't space for it. We are thinking of putting it on the roof deck and using it as a gardening table. Is there anything I can do to the wood so that it won't get beat up by the elements? Thanks, Ben.