Demilec. Sealection Agribalance open-cell, semi-rigid, polyurethane spray-foam insulation contains more than 10% renewable, agriculture-based products, says the firm. The material expands to fill the cavity, sealing cracks, gaps, and voids. It provides an R-value of 4.45 per inch. 877.336.4532. www.demilecusa.com.