Spray foam is a product consisting of two materials that react when mixed together and expand after being sprayed in place. This expansion completely fills a cavity to prevent air leaks and keep energy costs down.
An additional benefit of spray foam is that it blocks heat transfer from inside to outside during cold winter months and vice versa in hot summer months.
The two types of spray foam are:
Open cell spray foam consists of cells that are left open making it a more flexible material. It expands during installation and fills cracks, crevices and other hard-to-reach areas. The R-value of open cell spray foam is commonly around 3.7 per inch. It also functions as an air barrier because it adheres to uneven surfaces and blocks air leakage. Open cell spray foam is often used for interior walls because it is also a sound dampener when applied between studs.
Closed cell spray foam is made up of cells that are completely closed. It is a more dense and rigid insulating material with an R-value that is higher than open cell spray foam. Because of the rigidity of closed cell spray foam, it acts as a vapor barrier and adds structural stability during strong winds and storms.
Why does it matter?
When the air leaks that exist around the building envelope are sealed, conditioned air remains inside your home. This means your HVAC system is working less resulting in energy cost savings.
Spray foam insulation insulates and seals air leaks in one application creating a thermal barrier and sealing penetration points.