My house is a 1930's Tudor with a steep pitch (12/12), breathable slate roof on shiplap. It's well ventilated with gable vents. I don't plan on enclosing it or using it for anything but overflow storage. It has about 8" of old fiberglass between the ceiling joists over a plaster ceiling. This is in Denton, Texas where the summers are very hot. I'd like info on the best spray on insulation for between and on the rafters that won't cause dry rot in the future.