To learn more about R-value, see Roof Online’s R-value page.

The following table provides typical R-values for various materials. These R-values were taken from manufacturer technical data sheets and are the reported R-values per inch of actual products. In a few cases, the R-values we give were taken from a non-manufacturer source that we consider to be trustworthy and accurate. In all cases, this table is intended as a general guide to insulation R-values.  When calculating the R-value for a real-life installation, always refer to the manufacturer's data sheets for the actual, specific product you intend to use, or contact the technical department of the product manufacturer or material provider.

R-value is used in the United States. RSI is the metric equivalent. To convert R-value to RSI, divide the R-Value by 5.67826. To convert RSI to R-value, multiply the RSI by 5.67826.  

Material R-Value per Inch (ft²·°F·hr/BTU) RSI per Inch (K·m²/W) Source
Cellulose, Blown (Attic) 3.8 0.67 Cellulose Insulation Manufacturers Association
Cellulose, Blown (Wall) 3.8 0.67 Cellulose Insulation Manufacturers Association
Cellulose, Wet Spray 3.75 0.66 International Cellulose Corporation
Concrete, Lightweight Insulating 0.90 - 1.49 0.16 - 0.26 Siplast
Concrete, Structural (140 pcf) 0.08 0.01 Siplast
Fiberglass, Batt 3.14 - 4.29 0.55 - 0.76 Johns Manville
Fiberglass, Blown (Attic) 2.12 - 4.0 0.37 - 0.70 Johns Manville
Fiberglass, Blown (Wall) 4.0 - 4.3 0.70 - 0.76 Johns Manville
Fiberglass, Rigid Board 4.3 - 4.5 0.76 - 0.79 Johns Manville
Gypsum Board 0.90 - 1.12 0.16 - 0.20 United States Gypsum Company;
Georgia-Pacific
Mineral Wool, Batt 4.0 - 4.22 0.70 - 0.74 Owens Corning
Mineral Wool, Blown (Attic) 2.95 - 3.39 0.52 - 0.60 Owens Corning;
American Rockwool Manufacturing
Mineral Wool (Rigid Board) 3.8 0.67 Rockwool Group
Oriented Strand Board (OSB) 1.0 - 1.24 0.18 - 0.22 Minnesota Sustainable Housing Initiative
Perlite Cover Board 2.64 0.46 Johns Manville
Phenolic Foam Board 6.7 - 7.5 1.18 - 1.32 Dow Chemical Company
Plywood 1.0 - 1.24 0.18 - 0.22 Minnesota Sustainable Housing Initiative
Polyisocyanurate Insulation 5.0 (NRCA)
5.7 (PIMA)		 0.88 (NRCA)
1.0 (PIMA)		 National Roofing Contractors Association;
Polyisocyanurate Insulation Manufacturers Association
Polystyrene Insulation, Expanded (EPS) 3.85 - 4.5 0.68 - 0.79 Insulation Technology, Inc.;
ACH Foam Technologies
Polystyrene Insulation, Extruded (XPS) 5.0 - 5.5 0.88 - 0.97 XPSA (Extruded Polystyrene Foam Association)
Sprayed Polyurethane Foam (Closed Cell)) 4.9 - 7.1 0.86 - 1.25 Icynene, Inc.
Sprayed Polyurethane Foam (Open Cell) 3.7 - 4.0 0.65 - 0.70 Icynene, Inc.
Wood Fiberboard 2.5 0.44 Blue Ridge Fiberboard, Inc
Wood (Typical Hardwood) 0.7 0.12 U.S. Department of Energy
Wood (Typical Softwood) 1.4 0.25 U.S. Department of Energy