I need some advice. Here is my situation; I have a 24x24 cabin in the mountains, had it for about 20 years. The roof is metal with a 12x12 pitch. The problem I am having is it condensates terribly, at least that is what I think is going on. As I am no builder, I relied on the advice of a buddy that told me we could run 1x4 perlins across the rafters and then screw the metal to that. It is a dark roof so I am thinking that the roof heats up during the day, winter time, and condensates dropping the moisture into the insulation and then it freezes. When I show up and start a fire it melts and drips so badly it will get the walls wet. Do I have to rip the metal off and sheet the roof with plywood to stop this. I have asked SBS and they don't seem to know what to do. Any advice is appreciated.