The Science of Experience



Creating Stable R-Value with Open Cell Spray Foam

Posted by Emillie Lee

Aug 21, 2017 9:00:00 AM


When choosing insulation for a home, one of the most important factors to consider is R-value. R-value is a measure of thermal resistance, and it indicates how insulating a material is. Polyurethane spray foam insulation has a higher R-value than a lot of traditional insulation products including fiberglass. What's even more important, however, is that it maintains this R-value over time, with high quality spray foams maintaining their R-values for several decades.

To understand how the R-value of spray foam insulation remains stable, it's important to understand the way that this material insulates. The spray foam actually traps air, and it is the air inside the foam that accounts for the insulating effects.

During spray foam insulation application, two chemical products come together to create a foam-like matrix. Inside the foamy matrix, hot gasses become trapped within the walls of foamy cells. Initially the R-value is very high because of these gasses. As the smaller molecules of gas diffuse out, the R-value slowly decreases until it stabilizes. This process takes about 6 months. Once it is stabilized, it remains the same for decades.

When you look at R-values for spray foam insulation, it's important to remember that these R-values are the 6-month R values. A good spray foam, such as those sold by NCFI Polyurethanes, is between 6.5 and 7.0 per inch of thickness at 6 months. When first installed, the R-value is around 10 per one-inch thickness, and this decreases over time until the 6.5 - 7.0 level is reached.

To learn more about polyurethane spray foam insulation, contact NCFI Polyurethanes. We offer the equipment, training and products that you need to install sustainable insulation in homes.


Topics: R-Value