Old beadboard walls and ceilings insulation help needed!
1899 farmhouse in very rural Zone 5 with original beadboard walls and ceilings on first and second floors. Fiberglass batts in the attic. Blown-in insulation to exterior walls in poor condition and will be removed. No sheathing. True 2×4 studs.
For exterior walls: Removing original wood siding (much of it can be reused). How best to insulate up against the back of the beadboard wall? Prefer to use mineral wool batts and not spray foam. Can it go up against the back of the beadboard wall? Then add plywood or similar sheathing, house wrap, and then reattach wood siding? Should I apply some sort of air gap? Recommendations for how best to achieve this?
For attic: Should I remove the fiberglass batts and create an air block between the joists and beadboard ceiling. I read a recommendation to lay cardboard between joists and then spray an inch of foam to create air seal but also protect the back of the beadboard ceiling. Batts could be relayed after the foam. Agree? Other ideas?
HVAC: plan to use gas furnace combo for 1st floor heat. (crawl space had to be hand dug to create room for duct work) attic heat pump unit for heating/ cooling 2nd floor.
Thanks for any guidance.