I'm finishing a storage room in my house. General layout, room is 12' x 12', door on one wall, window on opposite wall, roof peak ~12' above the axis between the door and the window. Roof slopes down to either side, so the side walls of the room are about 6' tall, at which height they intersect the slope of the roof.
Now, there's about 4' of space between the side walls of the room and the exterior walls of the house. I want to use this as accessible storage. That means I need doors between the room I'm finishing and these unconditioned spaces. Wall studs are on 24" spacing, and they hold up the roof trusses, so I'm not comfortable removing one. That means the maximum dimensions of these doors are maybe 68" tall and 22" wide. This is obviously not a standard door size.
I could build a custom hinged door, but I'm considering building a custom barn door instead, both for aesthetics and for looser tolerances in the build and install. Thus my question: is it possible to seal an interior barn door to provide an acceptable level of insulation between a conditioned and an unconditioned space?