Foamed sheathing is primarily made from which material?

Foamed sheathing is primarily made from polystyrene, which is a type of plastic commonly used in construction. This material is favored for its excellent insulation properties, lightweight nature, and ease of handling. Polystyrene foams are created through a process that results in a rigid and durable material, providing effective thermal insulation when used in wall systems, roofs, and foundations.

Moreover, polystyrene sheathing helps to improve the energy efficiency of buildings by reducing heat loss, which makes it an ideal choice for foamed sheathing applications. The other materials listed, while useful in various construction applications, do not offer the same combination of thermal insulation, structural stability, and moisture resistance that polystyrene does as a foamed sheathing material.