Hello, any help would be greatly appreciated. I am preparing to reroof my house. I’m a little worried about the weight I will be adding.
Here is the current roof: 2/12 pitch. Cathedral ceiling with 18ft span from outer wall to wall running down the center of the house. 2x6 t&g decking sitting on 3.5" x 11 1/4" beams on 6ft centers. 1" beadboard insulation, 7/16" osb. shingles.
I would like to tear off the roof down to the 2x6 t&g, then add:
6in polyisocyanurate insulation
A “ventilation panel” made of 7/16" osb, 2x6 blocks as spacers, and 5/8" plywood (weight of one 4x8ft panel is 110 lbs.
Malarkey 401 self-adhered underlayment
Malarkey legacy shingles (275lbs/square)
The difference then in weight is that the panel adds perhaps 70lbs/32 sq ft, the shingles are heavier, I have 2 more layers of felt/underlayment than currently, and the insulation adds something (negligible surely) I would guess that the sum added weight would be on the order of 3 lbs/sq ft then.
I live in southeast Colorado. Snows can be substantial but we aren’t in the mountains.
In addition to comments on this additional weight, I’d welcome any comments on my overall roofing plan.