Industrial / Commercial - Building Restoration, Renewal, and Spray Polyurethane Foam Insulation Specialists


Why should I worry about wall strength?
Your walls are the main structural component of your home. In wood frame construction, the weight of the roof and any snow on the roof push down on the walls with a compressive force. Strong winds and wind gusts impose lateral loads onto your house walls that tend to distort the walls with a shearing force. Building codes require that walls be designed to withstand these loads. However, when walls are built to minimum standards, while safe, you may sense wall creaking during high winds or shaking when doors are slammed or the kids are actively romping about.



What is a shearing force?
A shearing force on a wall tends to distort the wall from its original shape as a rectangle into a parallelogram. To test a wall's resistance to the shear forces imposed by wind loading, engineers use a "racking test." An 8ft. x 8ft model wall is built and placed in a large frame. The base of the wall is secured to the frame and a horizontal (lateral) force is applied at one upper corner. The force increases in 400 lb increments until the wall structure fails.


What is the effect of Pella Roofing & Insulation's Polyurethane Foam insulation?
In a series of racking tests walls with and without spray-applied polyurethane foam insulation were compared.

Wall with No foam: 800 lb racking load
Wall with Foam: 2800 lb racking load

This shows that wall with Spray polyurethane foam installed can add up too 2000 lb of resistance to any shearing force. This again shows why our foam is superior over other types of insulation. When Pella Roofing & Insulation foam is sprayed into your stud walls and fully adheres to the exterior sheathing and studs, reinforcing both. With this added rigidity, there will be less wall movement due to shaking and vibration. Additionally your walls have greater than code required resistance to "Racking Events" such as hurricanes or other strong wind situations.

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Tel: (319) 223-5137