Made just like a SIPs panel, E-Rim Insulated Rimboard consists of a sandwich of OSB and polyurethane foam, providing a tightly sealed, R-14 barrier around the beltline. According to the firm, the product is 20 times more airtight than conventional rimboard, and tested thermal performance is 12% better than a conventional system. E-Rim is available in all standard floor joist sizes. 866.363.7267.