My husband and I purchased a 1985 double wide modular minus the metal frames sitting on a full basement. Insanity was the cause. We actually bought it to clean up our neighborhood. After hauling off 1 acre of trash, about 37 loads under a tall camper shell, plus 6 towed cars, 27 engines (you get the picture), we have started on the house. We had to gut it. We are running into a dilemma regarding insulating the vaulted ceilings which comprise half the house. The 11 foot wide rooms are spanned by 2x6s on 16in centers. The roof pitch is 2.5/12. Fiberglass filled each cavity and there was no venting. The north roof face shows much evidence of past leaking presumably from ice dams. There have been no leaks since we have had it. We have added screening at the soffits with the idea that we will add ridge vents. The problem arises in how we should accommodate the new venting and how we should add more space for insulation. The recommended ceiling insulation here is r-38. The structural engineer said that the 2x6s are adequate for the snow load and 1/2 in drywall that we plan to do. He also said that the main built up beam in the center will be able to hold and additional layer of 2x6s below the existing ones if we choose that route. We are limited to dropping the ceiling at the outer walls a maximum of 6 inches because of low clearance. Is fiberglass the best option? Or is there some other kind of insulation with more r value per inch? I know we won’t get up to r-38, but anything will be an improvement.
p.s. We were surprised when we removed the drywall and found no headers on the load bearing walls. That was a different project.