What material is typically used to construct rigid insulation boards?

The typical material used to construct rigid insulation boards is primarily plastic foam. Rigid insulation boards are often made from materials like expanded polystyrene (EPS), extruded polystyrene (XPS), or polyisocyanurate, all of which fall under the category of plastic foam. These materials are chosen for their excellent thermal resistance, lightweight characteristics, and moisture resistance, making them ideal for roofing applications and other insulation needs.

The other materials listed, such as synthetic rubber, coarse wood or cane fiber, and metal sheets, do not provide the same level of insulation efficiency or structural advantages required for rigid insulation. Synthetic rubber might be used in roofing membranes, coarse wood or cane fiber does not have the thermal properties needed for effective insulation, and metal sheets are not insulating materials at all. Therefore, plastic foam is the optimal choice for constructing rigid insulation boards due to its performance in building applications.