Hi,

I am building a traditional timber frame horse barn in SE Michigan (area 5a). Barn is 36×60 on a 12×12 grid with a center aisle running the length of the barn. The roof is a 12-12 pitch with 1.5″ T+G pine decking and metal roof. Siding is T+G cedar attached to horizontal 4″x4″ nailers 2′ OC running between the timbers. The barn has a 12’x24′ basement in two of the “stall” sections. Basement will hold water pressure tank and water lines to automatic waterers that are plumbed below frost line. Also may be used to for water storage for a (future) solar water heating system. Above the basement there’s a tack room. Above the tack room there’s 24’x36′ loft with a dormer. The main barn area will be uninsulated / unconditioned space. There may be 5-7 horses in the barn generating quite a bit of water vapor. I’d like to make tack room and loft above be heated space, possibly with AC in the summer. The basement will need to be warm enough to prevent the water in the pressure tank freezing. Wondering what approach to insulation / vapor barriers / WRB you would recommend. I’ve heard of horror stories where improper insulation of timberframe structure led to rotting away of timbers, so that is the primary concern. The barn is being framed as we speak, so we have some flexibility on approach. Appreciate any insights and suggestions.