Spray Polyurethane Foam, aka SPF, is a material that is made by combining two liquids (a polyol/resin and an isocyanate) as it’s sprayed onto the existing roof substrate. It creates a foam that expands 20 times in size to form a seamless foam surface. When the foam has expanded, this layer can be between 1 and 1.5 inches in thickness.
When the installation is complete, it will create a durable, waterproof renewable foam roof covering. SPF roofing is not the most known type of roofing material; the technology has been around since the 1960s for industrial, commercial, and residential facilities.