The invention relates to a coating for expanded polyurethane insulation, which coating comprises a metal layer, such as an aluminum layer, and a crystallized polyamide layer. The coating material is preferably laminated to the polyurethane insulation layer as the polyurethane insulation is expanded or formed and when the polyamide layer is in a glutinous or not substantially crystalline form. The insulation may further comprise extruded adhesive layers positioned between the expanded polyurethane layer, the metal layer, and/or the polyamide layer.