Replies

1. 
   KDESIGN | May 29, 2012 03:09pm | #1

   I don't think it would have any moisture problems.  You don't say what type of insulation you are using, but if the 10 mil vapor barrier is installed correctly, it should stop vapor before it gets to the insulation.  So any type of insulation should be okay.  The air gap ventilation will act as a backup measure to dry out any vapor that happens to get past the vapor barrier. 

   If you are using closed cell spray foam for insulation, many will tell you to omit the vapor barrier.  I would retain the vapor barrier no matter what type of insulation I used. 

2. 
   xxPaulCPxx | May 30, 2012 11:34am | #2

   Well, there is a significant difference between black asphalt shingles and standing seam metal... which do you have?

   Your air gap and radient barrier are a little wonky as well.

   Here is what I would expect to see, based on the ingrediants you list:

   1. Asphalt Shingles

   2. Tar paper (or Synthetic) underlayment

   3. Radiant Barrier sheathing

   4. 1x Furring providing air gap beween continuos soffit vent and ridge vent

   5. OSB/plywood deck (which I would tape the seams and put Tyvec/TYPAR on myself)

   6. 2x6 rafters

   7. R19 fiberglass insulation between the rafters

   8. plastic sheet moisture barrier

   9. Drywall (unless it's a bathroom, why use greenboard?)