Johns Manville Announces Higher R-Value for Insulation
Johns Manville announced that JM Corbond III closed-cell spray polyurethane foam insulation now delivers an R-value of R-7 per inch, a change that translates to a nine percent increase in thermal resistance compared to the previous R-6.4 per inch.
While maintaining its superior sprayability and signature lavender color, the product now requires significantly less product to deliver the desired R-value. For example, contractors now need only 5.5 inches of spray foam to achieve an R-38, compared to the previously needed six inches. This also means that contractors can achieve an R-21 in a 2x4 cavity with one three-inch pass.