Building Insulation, Thermacal, Therma, Vented Roofing Products, Roofing, Ventilated Sheathing, Nailbase Insulation, Commercial, Industrial, Nail Base, Insulation, Leed Credit, Polyiso, Polystyrene, Underlayment, Green Building; Insulation; Panels; Cornell Corporation has products that have performed day in and day out on roofs nationwide for longer than most of our competitors have been in the business! See the difference performance roofing insulation makes!; Insulated Building Panels & Vented Roof Insulation ...