Polystyrene has been around for longer than polyurethane and has experienced a widespread use. Polystyrene is used in everything from crafts to cups and extruded polystyrene foam is used in insulation.
Polystyrene is a synthetic aromatic polymer made from the monomer styrene which is also known as Styrofoam. It is the white brittle material that is frequently used in shipping to protect the goods inside.
Polystyrene is pre-formed to the steel panels and is usually glued to both the front and back of the inside of the panel. It maintains its shape and fits better than open cell polyurethane over a long period of time and does not degrade, deform, or lose R-Value. Most manufacturers use closed cell polyurethane negating many of the positives mentioned.
The less expensive of the two, polystyrene is a popular choice for insulating overhead garage doors because of its good value and simple installation. It’s manufactured in sheets, and panels are cut and attached to your garage door’s individual sections. It’s also waterproof and comes in various thicknesses. The thickness of your polystyrene will directly affect your insulation factor or R value. Typically, you can count on a rating of R2 per inch up to a value of around R10.