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. G&S Insulating has the training and expertise to properly advise you on the amount of insulation your home needs. Contact us to discuss your next project.