The primary load-bearing structures of your home are the walls.
For wood-frame construction, the walls are compressed by the downward-exerted force resulting from the combined weight of the roof, including trusses, decking, and shingles, as well as anything on top of the roof like debris or snowfall. Additionally, wind exerts a lateral force on your home's walls, potentially distorting their perpendicular framing with what building scientists call a “shearing force.”
All building code requirements mandate that residential walls be constructed to withstand these forces. Despite the implementation of these requirements, walls that merely meet the minimum requirements can be prone to movement (creaking, shifting, shaking, etc.) during high-wind events, like tornadoes or hurricanes.
High-density, closed-cell spray foam insulation can reinforce exterior walls when sprayed in stud cavities.
Closed-cell spray foam adheres to both the exterior sheathing and wall studs to enhance a wall assembly's overall structural integrity. By installing spray foam, an exterior wall becomes more rigid, thereby it is more resistant to compression and shearing. Therefore, it can be described as having a greater “racking strength” than a typical wall assembly. (sprayfoam.com)
Research conducted by the National Association of Home Builders (NAHB) has shown walls installed with closed-cell spray foam have a racking strength up to 300% greater than walls without it.
In one study, wall assemblies installed with and without spray foam insulation were tested. The two exterior-facing building materials examined included vinyl siding over 15 pounds of building paper and textured plywood siding. All wall panels were faced with half-inch drywall on the interior-facing side, with studs spaced 16 inches on-center.
In the SPF-applied group, the stud cavities of the wall assemblies were filled with closed-cell spray foam (1.5 lb./cu. ft. density). The graph indicates the wall assemblies that were installed with SPF added significant racking strength, as well as deforming less and offering greater resilience with each applied force. (Source: Test results are reported in "Testing and Adoption of Spray Polyurethane Foam for Wood Frame Building Construction" (May 25, 1992) prepared by NAHB Research Center for The Society of the Plastics Industry/Polyurethane Foam Contractors Division.)
With up to 300% greater racking strength, it’s no wonder that it is the only insulation approved by FEMA.
AICS can address issues and guide customers through their questions. Contact them and see their reviews at aicsnj.com.