R-values of Insulation and Other Building Materials

The American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) provides R-values of building materials in their 1997 Handbook of Fundamentals.

R-values are additive.  For instance if you have a material with an R-value of 12 and another material with an R-value of 3, then both materials combined have an R-value of 15.

Many energy modeling programs and code calculations require U-values of assemblies.  The U-value is simply the reciprocal of the total R-value of the assembly.

U Value Equation

Building Material R-Values

MATERIALTHICKNESS
R-VALUE
 Air Films  
 Exterior  0.17
 Interior Wall
  0.68
 Interior Ceiling
  0.61
   
 Air Space
  
 Minimum 1/2" up to 4"   1.00
   
 Building Board   
 Gypsum Wall Board
 1/2" 0.45
 Gypsum Wall Board
 5/8" 0.5625
 Plywood  1/2"
 0.62
 Plywood 1" 1.25
 Fiber board sheathing
 1/2" 1.32
 Medium Density Particle Board
 1/2" 0.53
   
 Insulating Materials
  
 R-11 Mineral Fiber with 2x4 metal studs @ 16" OC  5.50
 R-11 Mineral Fiber with 2x4 wood studs @ 16" OC
  12.44
 R-11 Mineral Fiber with 2x4 metal studs @ 24" OC
  6.60
 R-19 Mineral Fiber with 2x6 metal studs @ 16" OC
  7.10
 R-19 Mineral Fiber with 2x6 metal studs @ 24" OC
  8.55
 R-19 Mineral Fiber with 2x6 wood studs @ 24" OC
  19.11
 Expanded Polystyrene (Extruded)
 1" 5.00
 Polyurethane Foam (Foamed on site)
 1" 6.25
 Polyisocyanurate (Foil Faced)
 1" 7.20
   
 Masonry and Concrete
  
 Common Brick  4" 0.80
 Face Brick
 4" 0.44
 Concrete Masonry Unit (CMU)
 4" 0.80
 Concrete Masonry Unit (CMU)
 8" 1.11
 Concrete Masonry Unit (CMU) 12" 1.28
 Concrete 60 pounds per cubic foot
 1" 0.52
 Concrete 70 pounds per cubic foot 1" 0.42
 Concrete 80 pounds per cubic foot 1" 0.33
 Concrete 90 pounds per cubic foot 1" 0.26
 Concrete 100 pounds per cubic foot 1" 0.21
 Concrete 120 pounds per cubic foot 1" 0.13
 Concrete 150 pounds per cubic foot 1" 0.07
 Granite 1" 0.05
 Sandstone / Limestone
 1" 0.08
   
 Siding  
 Aluminum / Vinyl (not insulated)   0.61
 Aluminum / Vinyl (1/2" insulation)   1.80
   
 Flooring  
 Hardwood 3/4" 0.68
 Tile  0.05
 Carpet with fiber pad
  2.08
 Carpet with rubber pad
  1.23
   
 Roofing  
 Asphalt Shingles
  0.44
 Wood Shingles
  0.97
   
 Glazing  
 Single Pane  1/4" 0.91
 Double Pane with 1/4" air space
  1.69
 Double Pane with 1/2" air space
  2.04
 Double Pane with 3/4" air space
  2.38
 Triple Pane with 1/4" air spaces
  2.56
 Triple Pane with 1/2" air spaces
  3.23
   
 Doors  
 Wood, solid core  1 3/4"
 2.17
 Insulated metal door   2" 15.00

The R-values above for specific assemblies like doors and glazing are generalizations because they can vary significantly based on special materials that the manufacturer uses.  For instance, using argon gas in a double pane insulating glass unit will dramatically improve the R-value.  Consult manufacturer literature for values specific to your project.

The values in the table above were taken from a number of sources including: The ASHRAE Handbook, ColoradoENERGY.org, and Building Construction Illustrated by Francis D.K. Ching. Other minor sources were also used. Archtoolbox does not test materials or assemblies.

2004 CSI Masterspec Division

Thermal Protection: 07 20 00


 


Help make archtoolbox better. If you found an error or out of date information in this article, please let us know.


   

Related Archtoolbox Articles