Spray foam insulation is usually defined by its density. Density is measured by weighing one solid cubic foot of foam material. There are three main types of spray foam that are installed in homes. Open cell foams when used, typically have density around 0.4 to 0.5 lb./cu. Ft and Closed cell foam for insulation applications ranges in density from 1.7 lb./cu. ft. to 2.0 lb./cu. Ft. Different densities of foams are used in various combinations of layers for different insulation needs. Roofing applications use spray foam density around 2.8 to 3.0+ lb./cu. ft. to support traffic and loads better. Often 1 inch of two-pound foam is installed in exterior walls, which is then covered with other insulation products. Half-pound foam is the insulation which is typically found installed at the underside of roof sheathing and in exterior walls. Three-pound foam is generally installed on roofs. As the density of foam increases stronger and heavier it becomes. Many times polyurethane foams are molded into decorative interior molding and painted or stained to give wood effect. These “higher density” foams are typically in the 30 lb./cu. ft. to 40 lb./cu. ft. density range.