SPF is spray-applied in situ at a building site using two liquid components – MDI (the A-side) and polyol blend (the B-side). These are mixed under pressure and sprayed into wall cavities, roof underlays, basements, attics and/or crawlspaces. The reacting liquids expand and solidify into a foam matrix. This creates a seamless seal that fills the cracks and crevices from which hot and cold air, moisture, and even sound enter a building.
The market for SPF is growing as more builders turn to it to help meet building codes and green building certification requirements, such as the U.S. Green Building Council's LEED for Homes (LEED-H) and LEED for commercial buildings, and the U.S. Environmental Protection Agency's ENERGY STAR® rating.