Hi All, Just purchased a home in northern Michigan. Built in 1988 with 1" of TUFF R(?) foam under vertically applied cedar 3" T&G. After inspection there are 2x4 stud walls, 3 1/2" fiberglass insulation,plywood sheathing, 1" TUFF R foam, 5/4 cedar siding, and no drainage opening. I was trying to add insulation to the exterior. Thinking about ROXUL board directly over the cedar, furring strips, and different siding. Any thoughts on this plan.