Sprayed Polyurethane Foam is applied as a liquid using plural-component spray equipment. It then expands approximately 30 times its original liquid volume to form a hard, closed cell monolithic roof surface. The “A” and “B” components (isocyanate and polyol resin) are pumped from separate tanks or drums, into a specially designed proportioning machine. The materials are heated to a specific process temperature and proportioned to the correct ratio. The two liquid materials are kept separate until they pass through the machine, through the heated hoses and out to gun, where they are finally mixed and sprayed onto the substrate. The SPF is applied to a specific thickness defined by the specification. SPF is typically applied in ½ inch to 1-inch layers, or “passes.” Roof specifications or sloping designs that require more foam are applied in multiple passes. The SPF is sprayed down as a liquid, quickly rises in seconds, and can be walked on in minutes. The Polyurethane Foam dries within seconds after applied to the roof surface. Its expansion results in a weather tight roofing membrane that is fully adhered to the substrate. Because of polyurethane’s lightweight it adds little additional weight to the structure and is often used in remedial applications. Polyurethane Foam has a history of more than 35 years as a maintainable roofing medium. Polyurethane Foam adds excellent insulation value to the structure and utility bills can reflect the difference.
Once the SPF has been applied, a protective layer of elastomeric coating and/or gravel is applied. This protective layer produces a durable weather resistant surface and that can be walked on for normal maintenance. In cases of higher trafficability and durability, it may be recommended to use a Cementitious Topped Coated Foam Roofing System.
SPF adheres to just about everything so it can be installed over concrete, wood, steel, and most existing roof systems which saves on the expense of roof removal and landfill fees. SPF Roofing installers can spray apply a tapered roof system with the foam which eliminates the need for costly tapered insulation systems. The cants and vertical wall terminations are also spray applied making them an integral part of the roof system and minimizing additional component costs.
Spraying foam requires at great deal of training and experience to assure proper mixing of the foam is being achieved while maintaining a high level of productivity and quality of workmanship. Spraying foam is an art, and the more experience a contractor has, the better your roof system will look, flow, perform, and drain properly.
