Garage Door Insulation roll – 21″ x 36ft – Foam Core – Pure Aluminum Foil. Standart Garage Door Sizes: One car garage door – 4 panels x 21″ x 9 ft. You will need 1 rolls to insulate one car garage door completely.Two car garage door – 4 panels x 21″ x 18 ft. You will need 2 rolls to insulate two car garage door completely. FREE FAST SHIPPING!!!CUSTOMER SATISFACTION GUARANTEED!!! MATERIAL – 5mm (1/4 inch) closed cell polyethylene foam sandwich between Pure Aluminum Foil on both sides. The garage is usually the largest non-insulated space in your homes, resulting the costly heat loss and extra expense in your utility bills. Reflective Garage Door Insulation will STOP THE HEAT FLOW thru the garage door. START SAVING YOUR MONEY TODAY! ADDED VALUES: Will stop 97% of radiant heat transfer.Can reduce the inside garage temperature up to 20 degrees in summer and turn it into a comfortable working environment.Saves heating costs in winter, stop heat loss through the garage door.Creates an air pocket to obtain an R8 value insulationVery clean, finished lookNon toxic / Non carcinogenic