Reflective multilayer foil insulation is a high-performance all-in-one reflective breathable film and thermal insulation material. This high-performance thermal insulation material is both a perfect radiation barrier and improves ventilation and minimizes condensate to keep warm in winter and cool in summer. Reflective multilayer foil insulation is lightweight and easy to install in home and commercial applications, ideal for new construction or renovation, and can be installed on walls and roofs. Multi-layer foil is most commonly used to supplement rigid insulation boards, mineral wool boards and occasionally mineral wool glass wool rolls. The thickness of the product directly affects the calorific value provided. Thicker radiation blocking products may have higher R values. When the joist beams above the roof platform are installed with multiple layers of foil, special measures need to be taken to ensure that the possibility of condensation is avoided.