SPF Roof Benefits: Why Choose Spray Polyurethane Foam Roofing?

Spray polyurethane foam (SPF) is an incredibly versatile material that adheres well to various substrates, including concrete, wood, steel, and almost all types of roofing materials. This versatility provides a significant advantage over competing materials in roofing repairs or replacements, as it eliminates costly removal and landfill expenses by allowing SPF to be applied directly over existing roofing. 

SPF is particularly beneficial for installing durable roofing systems, specifically tapered roofing systems, because it enables installers to create a tapered design with just one material rather than needing several. SPF can also be spray-applied to cants and vertical wall terminations, thus integrating them into the roofing system and reducing the need for additional roofing insulation materials.

A Protective, Monolithic Solid Roof Shell Derived from Liquid Foam

Utilizing plural-component spray equipment, spray foam is applied as a liquid that expands approximately 30 times its initial volume, forming a hard, closed-cell monolithic roof surface that fills all cracks and crevices. Once applied to the roof surface, spray foam cures within seconds, creating a weather-tight roofing membrane that fully adheres to the substrate. Due to polyurethane's low mass, spray foam is frequently used in energy efficiency roofing applications without adding much weight to the structure. 

After the SPF has cured to its finish specifications and proper thickness, a layer of protective elastomeric coating or gravel is added on top. This layer not only provides a durable, weather-resistant surface but can also be walked on for routine maintenance. With a lifespan of up to 35 years as a maintainable roofing medium that offers excellent insulation value, spray polyurethane foam has been linked to energy efficiency, as reflected in lower utility bills. 

Durability

Contrary to the misconception that a "foam" roof is soft and easily damaged like seat cushions, SPF roofs are exceptionally durable and capable of withstanding construction and foot traffic. In the event of damage, polyurethane caulking can provide a simple repair solution. Although it is a rigid system, it can sustain minor damage from tools or other objects. 

R-Value From Density

Higher density in SPF correlates to a higher R-value and greater strength, making density crucial for effective thermal resistance. While specific values can vary by manufacturer, spray foam with a density of 3 lb. offers an R-value of 7.14 upon installation and 6.86 as it ages, with a compressive strength of about 50 psi. The typical range of density for foam roofs is between 2.5 lbs. and 3 lbs. per cubic foot. An example showcasing the insulation capabilities of SPF roofs can be seen in a recent project in a Southern Oregon school district, where SPF was installed on several relocatable classroom buildings. Those classrooms, equipped with a 1.5-inch layer of 3 lb. density foam and an acrylic coating, experienced a remarkable 50 percent saving on energy costs, significantly reducing air conditioning usage during peak times. 

Lifespan

The lifespan of a spray foam roof can extend considerably if the protective coating is regularly maintained. Depending on the thickness of the coating, the roof should be cleaned, primed, and recoated every 10 to 15 years. With proper care, a quality SPF roof can last for 50 years or more. 

No Seams

Spray polyurethane foam applied to the roof surface creates a seamless system, preventing water and air infiltration that can occur through traditional seams. This seamless design eliminates problems such as ice damming during winter and water pooling, which can increase the roof's weight and contribute to structural failure over time. Additionally, spray foam creates a self-flashing system that minimizes leaks often associated with other products. When applied, it conforms to the roof substrate, effectively flashing mechanical equipment, skylights, and parapet walls. 

SPF Roof Cost

Various factors influence the cost of an SPF roof, as is typical with any roofing system. Generally, basic SPF roofing systems start around $2.50 per square foot. Costs can fluctuate based on geographical location, project complexity, accessibility, foam thickness, and the type of foam coating system employed. 

Spray Foam Roofs’ Protective Coatings

After the SPF has been applied, a protective layer, whether gravel or an elastomeric coating, is added to enhance durability and create a weather-resistant surface. This layer is suitable for regular maintenance activities.

Cool Roofs Program and Benefits of ENERGY STAR products

Roof coatings designated as ENERGY STAR qualified can significantly reduce energy bills by up to 50 percent and decrease the demand for air conditioning in buildings. These products are part of the Cool Roof Program, which sets standards for roof reflectivity and maintenance. Light-colored roof coatings can lower rooftop temperatures by up to 100 degrees, effectively reflecting UV rays and heat.

A Lightweight System

In contrast to traditional roof insulation for built-up roofing systems, which averages nearly three pounds per cubic foot, a spray polyurethane foam roofing system weighs approximately 60 pounds per 100 square feet per inch of foam applied. This results in a spray foam roof that is roughly 10 percent of the weight of a conventional built-up roofing system (600 pounds per 100 square feet), making it easier to maintain.

Versatility

Spray foam roofing systems are adaptable for both re-roofing existing structures and protecting new construction. SPF can be applied not only to flat surfaces but also to domed, saw-tooth, pitched, and sloped roofs.

Installing an SPF Roof

SPF roof installation involves various critical procedures tailored to existing roof structures, making it essential to comply with local and state building codes and utilize the appropriate materials.