There are steel, aluminum and wood units that feature insulation. In some models, it is a main feature while in others it is optional. Each insulated unit has a measured R-value.
The steel insulated doors can have a structure consisting of two, three, four or five layers. When there are only two layers, one of them is the front steel layer and the other one is the insulating material. The material can have vinyl backing for greater durability, but this backing is not considered to be a structural layer. There are two types of three-layer construction. There may be two front steel layers one after the other and a third layer of insulation. It is also possible for the insulating material to be surrounded by one steel layer on each side.
With the four-layer design, there are two steel sheets at the front followed by the insulating material and another sheet of steel. The models from the Canyon Ridge collection have a five-layer structure: overlay, cladding, steel sheet, insulating material and another steel sheet.
The doors made by the company come with either Intellicore or polystyrene insulating material. The Intellicore insulation is polyurethane foam which is sprayed between the two surrounding structural layers. The material has high R-value and is highly resistant to damage. The polystyrene insulating material comes in panel form. It is directly attached to the back of the front metal sheet.
The Clopay insulated garage doors made from wood have polystyrene panels set inside the hollow hemlock frame between the base face material and the inside skin layer. In order to get a higher level of thermal resistance, the glass units can be constructed with insulated glass panels.