The purpose of insulation is to contain heating and cooling efficiency in insulted areas. In some cases in wall construction, it is used as sound barriers as well.Spray foam can be used as an insulating and air sealing product for residential wall and ceiling cavities. The insulation is sprayed, via special equipment, into wall cavities and expands to fill all the nooks and crannies in a wall cavity. Excess foam is scraped off the studs to form a uniform wall cavity. Spray foam insulation makes it easy to completely fill wall cavities with insulation and to perform air sealing in the same step.