I've got a doublewide that has no access to the attic area, plus a lot of it has vaulted ceilings so there is no room up there to start with. When I reroofed this place a few years ago I had to replace some of the decking. I noticed that the insulation in the ceiling was next to nothing but didn't do anything about it at that time. Years later after a lot of high utility bills I have decided to insulate the roof. After talking with different contractors the best way to do this for the best performance was to use closed cell foam. Their idear is to use 2 x 4s on top of my shingles with the 3 1/2 side standing up and build a frame work on top of the roof, then spray the foam between the 2 x 4s directly on top of the shingles and then I plan to top that with a metal roof. Has anyone seen this done before or do you think I'am wasting my money? Would appreciate any comments.
Not knowing how much of your home is vault we have added insulation to mobile home roofs by removing the roof vents and gaining access to the attic per say and have it reblown with insulation. double wides in our part of the country have vents on the shingle roof that are easy to remove with i think three screw how ever we put back a 14 inch vent so that we can make a little bigger hole to access space and allow better venting of that part of the house
If your home has a vented attic area, adding insulation on top of the roof will do no good. You will still have the airflow up through the eaves and out whatever roof vents there are. That is still going to remove heat from the living space.