metal roof with no sheathing

Thanks, Todd, for your speedy reply. Had the job been done as per plan, I don't think we'd be having this conversation. I'm looking for options: either removing the roof or whatever.

Hello, To make a long story short, last summer my husband and I had a 30 x 40 garage with a loft built. A relative built it and convinced my husband, contrary to the plan, that OSB wasn't necessary. The metal roof was installed over purlins with no underlayment or vapor barrier. The building does have a ridge vent and vented soffits. I use the loft for storing furniture, etc. and am concerned about condensation, and insects and rodents entering the building through the openings of the ridges of the metal roofing. We live in the country and the loft is already filled with cluster flies. We spent a lot of money to build this garage and I am beside myself that corners were cut when it came to the roofing. I have told my husband that in the spring we should remove the metal and put down OSB and felt and do it right. Is this feasible (other than costing a lot of money)? Can the roofing be saved and reused? It was screwed in. Would the purlins need to be removed? I'd appreciate any advice. It is a gorgeous building that is making me physically ill every time I drive into the yard. -D