Vapor barrier placement / Discussions

Building a 24 X 50 Post and Beam Barn.  Planning to insulate on the exterior with no interior insulation as I wish to keep the bones of the barn exposed internally.  Wall currently has 3/4" Shiplap pine sheathing over the Girts.  Looking at emplacing 4" R20 Rigid XPS Panels seam taped. Those would be strapped to the wa...

...barriers in homes with air conditioning can be a problem, particularly in more humid climates and if the home is kept at very low temperatures. If you are insulating and heating the cottage I would definitely include a vapour barrier. It will also act as an air barrier if you tape it well, so it will be more efficient ...