Air Krete - the world's only fireproof, non toxic insulation. Air Krete is foam made from air and minerals. It is a magnesium cement foam that offers a superb R-value while sealing air leaks 100%. It can be installed in almost any situation. R-value is 3.9 per inch. 2-hour UL listed Firewall. Mold proof. Pest Resistant. Zero VOC. Non toxic. Non allergenic. Never shrinks or settles. The best choice for insulation in new or existing buildings to make them excel in energy and comfort.