Spray Polyurethane Foam (SPF) is an eco-friendly roofing option for commercial, industrial and manufacturing facilities. Spray Polyurethane Foam, more commonly referred to as SPF, is a material that is sprayed as a liquid, so it can expand into a foam, creating a solid layer across an existing roof.

How Roof Coating Insulation Works

The first layer put down by the contractor is the polyurethane foam. This foam is created by combining two liquids (a polyol/resin and an isocyanate) as it’s sprayed onto the existing roof substrate.

As the liquid is sprayed onto the existing roof, it creates a foam that expands 20 times in size to form a solid, seamless foam surface. When the foam has expanded, this layer is usually between 1 and 1.5 inches in thickness.  Since the polyurethane foam adheres to most common surfaces, it can be installed on any roof slope.

When the SPF layer has been completed, it is then coated with a layer(s) of elastomeric silicone or acrylic coating with embedded granules. This layer is generally between 20 and 30 mils (a mil is a thousandth of an inch — .001 inch.) in thickness. The coating protects the roof and SPF from UV light, weather, normal wear and provides the required fire ratings.