04 Feb

What is the R-Value of Common Insulations?

When insulating, it’s good to know what R-value different insulations have.

WAP_bannerFor walls, for example, if you’re told the Code Enforcement Officer is going to require R-21, remember that the OSB on the walls of your house, and the clab boards and drywall both on theĀ inside andĀ outside of your house also have an R-value. So when you spray three inches of foam on the walls that has an R-value of 19.8, the other materials involved in your wall structure will surely have a large enough value to give you the required R-21.

Something else to consider is that Code Enforcement Officers usually don’t tell you that the RESNET program they used to calculate proper R-values for your roof (usually around R-38 to R-49) will allow the wall R-value to supplement what’s needed for the roof, and vice-versa


Typical R-Values for Common Insulations (per inch) are:

  • Vacuum Insulated Panels – R-30 to R-50
  • Polyurethane Rigid Panel – R-5.5
  • Closed Cell Foam (aged after 30 days) – R-6.6
  • Water Blown Spray Foam – R-5.2
  • Thinsulate Clothing Insulation – R-1.6 to R-2.9
  • High Density Fiberglass Batts – R-3.6
  • Rice Hulls – R-3.9
  • Cotton Batts – R-3.7
  • Icynene Spray Foam – R-3.85
  • Open Cell Spray Foam – R-3.6
  • Cardboard – R-3.6
  • Rock Wool Batts – R-3.4
  • Cellulose Loose Fill – R-3.4
  • Fiberglass Loose Fill – R-3.0
  • Wood Panels used for Sheathing – R-2.7
  • Straw Bale – R-1.45
  • Softwood – R-1.41
  • Wood Chips – R-1.0
  • Snow – R-1.0
  • Hardwood – R-0.71
  • Brick – R-0.2
  • Glass – R-0.14
  • Poured Concrete – R-0.08

If you have any questions please do not hesitate to contact me.

Dr. Sprayfoam (Mark Gugino)

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