What material is typically used to construct rigid insulation boards?

Rigid insulation boards are predominantly made from plastic foam, which is effective in providing thermal resistance. The most common types of plastic foam used in rigid insulation are polystyrene (EPS and XPS) and polyisocyanurate. These materials offer a combination of low thermal conductivity, excellent moisture resistance, and durability, making them ideal for various roofing applications.

While coarse wood or cane fiber may have applications in insulation, they do not typically provide the rigid structure that is characteristic of insulation boards. Instead, rigid boards are designed to maintain their shape under pressure and provide a continuous barrier against heat transfer. Therefore, the reliance on plastic foam is key to the insulation's effectiveness in both residential and commercial building projects.