Hi! I am from southern Ohio and have been looking around at pole barn kits from both dealers and lumber companies and there seems to be a varying opinion of what is best as far as the roof is concerned...Some of the places that I talk to want to use purlins 2' OC, 7/16" OSB and roof felt underneath the metal roof of a pole barn while other places just have roof purlins 2' OC and insulation (the insulation with the silver backing) underneath the metal roof. Is one approach any better than the other? Since this will be a horse barn, I would like a decent moisture barrier on the roof to help to diminish "sweating" during the summer. The OSB seems to add a little over a $1,000 to the cost of a barn so I want to make sure that it's worth it before going that route. Thanks for any advice, recommendations, etc.