Polyurethane vs Polystyrene for Garage Door Insulation

Insulation in your residential or commercial garage door is essential if you want to make sure you keep the cold temperatures out of your house. There are two main types of insulation which are Polyurethane and Polystyrene.

Polyurethane and Polystyrene


Polyurethane (right) is a polymer composed or organic units joined by urethane links. They were first made by Otto Bayer and his coworkers at IG Farben in Leverkusen, Germany in 1937. It is mostly used in construction, car seating, and furniture but it is used in many other applications.

Polyurethane is sprayed into each panel and makes a very tight fit which will add to the rigidity of the panel when it is new giving it a higher R-Value .

Polyurethane is the more expensive material of the two but doesn’t usually add too much more money to the price of the door. It is important to make sure that the steel skins of the door are not too thin because two things could happen. One, the door will dent easily or two, small waves will appear across the sections and can generally be seen within five feet. This will obviously make the door not look so hot.


Polystyrene (left) 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 it shape and fits better than open cell polyurethane over a long period of time and does not degrade, deform, or lose R-Value. Most manufactures use closed cell polyurethane negating many of the positives mentioned.

Polystyrene does not fit as tightly as the urethane foam in the end corners of each panel, leaving air pockets. Some manufacturers do not glue their polystyrene to the panels so it does not add to the stiffness of the panels. Generally, this foam results in a lower R-Value for the door.

Of the two materials, polyurethane is the better material. It does have a slight price increase and it’s up to you to decide if it is worth it or not. Regardless, getting insulation is a good choice no matter which material you use.

Thomas V. Giel Garage Doors serves a 50-mile radius around Pittsburgh. We handle all your needs when it comes to garage doors! We serve residential and commercial, and our maintenance programs help make sure your garage doors work over long periods of time. Contact us today!