Hollow Metal Doors are made of channel reinforced steel sheets and filled with insulation materials such as polystyrene or polyurethane. Standard metal doors are 1 ¾″ thick and are prime coat painted. The gray primer finish is suitable for painting.
Hollow Metal Doors are shown to have superior performance for strength and durability compared to the alternate materials. Metal doors can take more abuse, are more sanitary, and much easier to maintain than wood or aluminum doors. A result of the strength and durability of steel is that metal doors have the lowest total cost of ownership of any other materials.