Insulfoam is the largest manufacturer of expanded polystyrene (EPS) in the U.S with 11 manufacturing locations throughout the country. Insulfoam's growth over the years has been accomplished by establishing fully diversified, state-of-the-industry regional EPS manufacturing facilities, demonstrating a high level of customer service and a competitive edge. Commonly used as a rigid plastic foam insulation, expanded polystyrene offers a high, long-term R-value for the following applications: