While it’s not technically an insulation product, the EcoStud system from Superior Polymer is a game changer for insulating concrete block and poured concrete walls. The plastic studs don’t suffer the same thermal transfer (and rust) problem as steel, and can be placed in direct contact with concrete. For retrofits especially, where basement walls may not be properly waterproofed, I’d consider this product a durability upgrade from wood furring—and an energy upgrade from steel studs. LEED data rates the system at about an R-20 when used with 3” of spray-in closed cell foam. Most impressive, the manufacturer uses 100% recycled plastic resins (post-industrial waste) as a base material.
www.superiorpolymer.com