carydf
New Member
We removed a dozen skylights from a heated porch. Each old skylight cavity has been covered with 3/4" ply and the porch has been re-roofed. There is no venting from the old skylight boxes. There are two options for insulation:
a) Glue 2" solid insulation tight to the underside of the roof sheathing, fill edge gaps with canned spray foam, drill holes in the rafters to allow some venting, add a layer of R13 fiberglass insulation w/paper vapor barrier, then drywall over.
b) leave a 1.5" gap between the roof sheathing and the 2" solid insulation and drill holes in the rafters to allow some minimal air movement, fill edges with canned spray foam, add a layer of R13 fiberglass insulation w/paper vapor barrier, then drywall over.
Which option is best?
a) Glue 2" solid insulation tight to the underside of the roof sheathing, fill edge gaps with canned spray foam, drill holes in the rafters to allow some venting, add a layer of R13 fiberglass insulation w/paper vapor barrier, then drywall over.
b) leave a 1.5" gap between the roof sheathing and the 2" solid insulation and drill holes in the rafters to allow some minimal air movement, fill edges with canned spray foam, add a layer of R13 fiberglass insulation w/paper vapor barrier, then drywall over.
Which option is best?