SPF Strength and Resiliency
Constructing resilient homes has become a target of architects, builders, code officials, and local governments. The purpose of building a resilient home is to create a structure that is better able to withstand a variety of weather-related challenges that it may encounter. When it comes to creating a resilient structure, strength and durability are especially important.
Spray polyurethane foam (SPF) insulation is recognized for its strength and durability to help protect homes in a number of ways. When properly applied, SPF insulation expands its size, which helps close gaps creating an air barrier, and reduces vulnerabilities throughout the structure. And because SPF adheres to the substrate – acting like a glue – it makes the wall system more durable. This added strength and stability from the SPF insulation can enhance the structural integrity of homes for years.
Walls are a key structural component within homes. Strong winds and gusts from storms can impose lateral forces, which can distort walls with what is called a “shearing force.”1
To quantify the strength of this insulation, “racking tests” are conducted to examine a wall assembly’s ability to resist shearing forces. Research conducted by the National Association of Home Builders (NAHB) found walls installed with closed-cell SPF have a racking strength of up to 300 times greater than those without. The results of two tests found that walls with closed-cell SPF not only added notable racking strength, but also deformed less and offered greater resilience with each applied force.2
The increased strength has also been found to reduce the need for additional building components, like studs, sheathing, and corner bracing. Special bracing for wind resistance is not required for walls that use closed-cell SPF due to the material’s ability to adhere to surfaces.
Keeping the roof on your home in a severe wind and rain event is key to making your home more resilient and disaster-resistant. SPF can also provide enhanced protection to roofs on homes with unvented attics (UVA). These attics are insulated and sealed as part of the building envelope. Roofing SPF is installed and adheres to the roof deck and attic walls. It can offer a compressive strength of 40 to more than 60 pounds per inch, which allows homes to better resist wind uplift.3 Wind uplift is common in areas where severe winds—hurricanes, tornados, or thunderstorms—enter homes through doors, windows, and other openings to create pressure under the roof. This pressure can cause damage or even the removal of a home’s roofing system. SPF under a roof deck has been shown to provide up to three times the resistance to wind uplift in a home.4
These are just some of the reasons why so many homeowners concerned about resiliency turn to SPF insulation.