BASF. Enertite open-cell polyurethane water-blown spray-foam insulation offers an R-value of 3.5 per inch for use in walls, roofs, attics, and rim joists, and it also provides a sound barrier for use on interior walls. The one-step product expands to fill the wall cavity, including in and around difficult-to-reach areas such as pipes and wiring for a seamless barrier. 888.900.3626.