Spray polyurethane foam is an insulating foam plastic that's sprayed on as a liquid that expands many times over. Thanks to specialized equipment, application techniques can achieve dramatically different results. The same raw materials, for example, can be made fairly rigid and soft to the touch. They can also be made into roofing foam that's resistant to foot traffic and water. Spray polyurethane foam doesn't just provide an air barrier and method of moisture control -- it also can offer high levels of R-value. Spray polyurethane foam can be used to insulate roofing, air barriers, walls, ceilings, attics and basements. It's effective at low and high temperatures and can provide a more ideal environment for your home's ventilation system so that it functions more efficiently.