Spray Polyurethane Foam (SPF)
Foamed-in-place polyurethane foam, typically referred to as spray polyurethane foam (SPF), is a closed-cell, higher-R-value foamed plastic insulation that is fabricated by an installer at the home site from two liquid components. Closed-cell foams insulate differently from conventional mass insulations. For example, а Iм sample of polyurethane foam consists of millions of tiny closed plastic cells filled with an inert gas. The inert gas resists heat transfer better than regular air.
Application equipment allows for the materials to be metered, mixed, and then either sprayed in place or poured into cavities. A cousin to SPF insulation is the single-component foam. Typically used for sealing around windows, doors, etc., it is available in spray cans at just about any hardware or home improvement store.