What is the proper thickness of spray foam insulation?

Many factors determine how thick spray foam insulation needs to be. All insulation is rated by R-value which is a rating of thermal resistance. The higher the R-value, the higher the thermal resistance. When installing fiberglass insulation, cellulose insulation or mineral wool insulation R-value is clear. Understanding the R-value of spray foam insulation is a bit different. Spray foam insulation R-value depends on the type of spray foam insulation being applied.

There are two types of spray foam insulation: open cell and closed cell. Depending on the manufacturer, open cell spray foam insulation has an R-value of approximately 3.5 per inch. It is a low-density product that is often used in interior walls and other areas that require some moisture permeability. The R-value of closed cell spray foam insulation is different. Depending on the manufacturer, closed cell spray foam has an R-value ranging from 5.0 to 7.0 per inch. Closed cell spray foam is more rigid than open cell spray foam and is used in areas where moisture permeability and a higher R-value are necessary.

To be sure your home has the right amount and type of insulation, consult a qualified insulation contractor. Whitson Insulation of Grand Rapids has the training and expertise to properly advise you on the amount of insulation your home needs. Contact us to discuss your next project.