Frequently Asked Questions
No, these insulation products are quite different. EPS is closed cell expanded polystyrene, while XPS is a closed cell extruded polystyrene. The properties, applications and costs of each are quite different. The majority of ICFs are manufactured with EPS.
Polystyrene is virgin material, manufactured from petroleum. Polystyrene beads are expanded with steam heat to be up to 40 times their original volume and then the expanded beads are molded again by steam heat into 25⁄8″ rigid insulation panels to create a Fox Blocks ICF.