How Thick Should Blown Insulation Be
When Blown into Attics and Wall Spaces, Loose-Fill Fiberglass Offers an Average R-2.5 Thermal Value per Inch (The Higher the Number, the Greater the Insulating...
When blown into attics and wall spaces, loose-fill fiberglass offers an average R-2.5 thermal value per inch (the higher the number, the greater the insulating effect). You’d need a thickness of about 7.5 inches of insulation to match the insulating value of a batt of R-19 insulation (R-19 is a common batt value).
What is the R-value of 12 inches of blown insulation?
The number is presented per inch, so an R-value of 3.1 at 12 inches would provide an overall value of R-38.
What is the R-value of 4 inches of insulation?
For areas with 3-4 inches of existing insulation, you will need an R-value of 38-49. For insulating flooring, you will need an R-value of 25-30.
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