Knauf Insulation’s new JetSpray Thermal Insulation System is a spray-on glass mineral wool that fills any net-less, side-wall cavity for acoustic and thermal insulation. The alternative material installs easily around wiring and other obstructions; provides R-values of R-15 when installed in a 2x4 wall cavity and R-23 in a 2x6 cavity; and reduces sound transmission up to 5 STC points. The spray’s glass fibers are mold-resistant and do not support microbial growth, says the company. JetSpray typically dries within 24 hours, so drywall can be installed the next day. Check with installer for pricing.