Glen writes from Stayner, Ontario, Canada: "I am insulating a sloped ceiling, starting with 1" codeboard cut tight between rafters, then R-20 pink insulation between rafters and then 1" codeboard 4x8 sheets over the face of the rafters and then 3/8 drywall, the rafters are 2x8 and my question is: will 1" -1 1/2" of air space be adequate? P.S. the roof is facing the north."

Answer: Codebord® insulation should not be used directly under a roof deck in this assembly. Check with your local building code for an appropriate installation.