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If it were mine in a garage space that had some heat in it and I wanted to keep it in there at least part of the year and usage was not excessive and the rest of the time it was covered. I would just repaint the garage with a gloss paint suitable for a bathroom and let a little condensation happen and just evaporate between uses and not worry about it.
Thanks everyone, going to go with the gloss paint and maybe install a ceiling fan to circulate. Steve