Roof insulation with I-beam rafters
I have built a shed roof using iLevel “2 x 10″ rafters. These have an I-beam profile. They are 16″ on center. I want to insulate the cathedral ceiling to R30 using fiberglass insulation. The width between the narrow part of the I-beams is 15 1/2”. That’s a problem as insulation is cut for 14 1/2″ width. Also, I want a 1″ air space above the insulation so I need 8 1/2″ thick insulation. I see that Owens-Corning has that (R-30C). Another problem is the blocking that separates the soffit spaces from the rafter bays is made from the same iLevel I-beam material. There are 2 gaps, one on either side of the blocks but I need some holes for the air flow in that top 1″ of space. I guess I’ll drill some holes in that 2″ x 2″ that is at the top of the blocking. Is that what you guys have done?