Look for the following related to the attic thermal envelope:
- Insulation type (if known);
- Insulation depth (SOP item);
- Vapor barrier installed under insulation;
- Radiant barrier installed (correctly);
- Radiant barriers must be installed in a manner that allows air to flow along the underside of the roof sheathing. Failure to ventilate the sheathing may void the shingle warranty.
- Radiant barrier sheathing (RBS) is roof sheathing with foil bonded to the underside. (See my article on Sheathing).
Comment if attic is configured as conditioned space:
Closed cell foam installed against the underside of the roof sheathing may hide leaks, allowing the structural integrity of the roof sheathing to become severely compromised from advanced wood decay before the leak is discovered. For safety reasons, inspectors should bear this in mind when walking roofs with deteriorated roof-covering materials and attics insulated with sprayed foam.