Hi: This is my first time posting on this site although I have been here many times as there is a wealth of information here. My question is I am getting my shingles replaced and I live in an older storey and half house with knee walls and part of my roof is my ceiling. The attic is a finished bedroom and the only insulation I have is what is in the cavities of the rafters above. It is like a catherdral ceiling. All the the insulation I have is what is between the rafters, about 4" which has been there for at least 30 years. What I am planning on doing is when the contractors replace the roof I am going to get them to remove the old insulation by removing some of the roof boards and use spray foam from the top as a replacement which will give me more bang for the buck I think. The question I have is one contractor says no problem in using foam and spraying from the top and leaving an air gap between spray foam and sheeting. The other contractor seems hesitate on wheather you can do that and still leave a nice air gap. Who is right? I was planning on putting on a steel roof over this but I am now considering shingles as cost is rising. Right now I do have some problems with ice daming and the uspstairs is cold in winter and hot in summer. Any other thoughts on this project is appreciated. Thanks