I wish to insulate a cottage. It has a cathedral ceiling and I'm looking for a specific rigid nailable roof insulation product. The product was showcased on *** ****s' Home Again Episode # 5 titled "Cabin in the Woods". Unfortunately I didn't catch the name of the product or the manufacturer. I am not interested in the typical nailable roof insulation --that being a polystyrene core adhered to OSB board-with or with out ventilation. This product was a one piece rigid board that provided insulation and allowed you to shingle directly to it. Can anybody enlighten as to what this product is and the manufacturer is??