The word Styrofoam sheet is often used to describe Expanded Polystyrene (EPS) foam; however, ‘Styrofoam’ is actually a trademarked term for closed-cell extruded polystyrene foam made for thermal insulation and craft applications. EPS foam is the correct term for any form of expanded polystyrene.
Expanded Polystyrene Board is a lightweight, rigid, closed cell insulation. EPS is available in several compressive strengths to withstand load and back-fill forces. This closed-cell structure provides minimal water absorption and low vapor permanence.
Styrofoam as people call it, is used in construction as a form of insulation. Sheets of Styrofoam are used to insulate the floors, walls, pipes and roofs on the interiors of all sort of buildings. Styrofoam insulates buildings from extreme temperatures and moisture, protecting you from the outside elements, and also provides a barrier for sound.
How Styrofoam sheet Insulates
Styrofoam sheet is made mostly of air, meaning it is a poor conductor of heat, but an excellent convector. It traps the air in small pockets, blocking the flow of heat energy. This reduces both conduction and convection and makes Styrofoam a good insulator. On the other hand, conductors such as metal are poor insulators because energy flows through them. Glass and air are other examples of good insulators. Styrofoam is placed in wall cavities to keep the inside of buildings warm. It traps air and reduces the transfer of heat energy, keeping heat inside the building.