GacoFireStop is the first open-cell foam approved for use in attics and crawlspaces with no additional ignition barrier. According to the maker, the insulation has passed the AC 377 Appendix X test for flammability twice: shaved, and with the skin on. It’s NFPA-approved for 12-inch-maximum wall thicknesses and 16-inch-maximum ceilings. Installation costs for an R-19 wall assembly average $3 per square foot, and for an R-38 ceiling about $6 per square foot. Gaco Western, 877/699-4226, gacowallfoam.com
