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What are R-Values of Building Materials?

Q: What are R-values of building materials? Can R-values be added to get the total R-value?

The R-value is an insulating property of a material, also referred to as the thermal resistance. Based on particular materials that manufacturers use, the R-values vary considerably. For R-values individual to your project always check manufacturer literature.

R-Values can be added. R-final (or R-total) is calculated as the sum of the single components:

R1 + R2 +… + RN = R-Final

for example

R5 + R3 + R2 = R10

R-Values of building materials are listed in the table below. To learn about recommended R-values tailored to your zip code visit ZIP-Code Insulation Program.

Material Inches R-Value
     
Insulation    
Expanded Polystyrene (extruded)   5.00
Polyurethane Foam   6.25
Polyisocyanurate (foil faced)   7.20
R-19 Mineral Fiber, 2×6 metal studs  16″ o.c 7.10
R-19 Mineral Fiber, 2×6 metal studs  24″ o.c 8.55
R-19 Mineral Fiber, 2×6 wood studs  24″ o.c 19.11
R-11 Mineral Fiber, 2×4 metal studs  16″ o.c 5.50
R-11 Mineral Fiber, 2×4 wood studs  16″ o.c 12.44
R-11 Mineral Fiber, 2×4 metal studs  24″ o.c 6.60
     
Concrete Block and Masonry    
Common Brick 4″ 0.80
Concrete Masonry Unit 4″ 0.80
Concrete Masonry Unit 8″ 1.11
Concrete Masonry Unit 12″ 1.28
Concrete, 60 pounds/ cu. ft 1″ 0.52
Concrete, 70 pounds/ cu. ft 1″ 0.42
Concrete, 80 pounds/ cu. ft 1″ 0.33
Concrete, 90 pounds/ cu. ft 1″ 0.26
Concrete, 100 pounds/ cu. ft 1″ 0.21
Concrete, 120 pounds/ cu. ft 1″ 0.13
Concrete, 150 pounds/ cu. ft 1″ 0.07
Granite 1″ 0.05
Sandstone / Limestone 1″ 0.08
     
Flooring    
Hardwood 3/4″ 0.68
Carpet, fiber pad   2.08
Carpet, rubber pad   1.23
Tile   0.05
     
Glazing    
Single Pane 1/4″ 0.91
Double Pane 1/4″ air space  
Double Pane  1/2″ air space 2.04
Double Pane  3/4″ air space 2.38
Triple Pane  1/4″ air space 2.56
Triple Pane  1/2″ air space 3.23
     
Siding    
Vinyl/Aluminum (no insulation)   0.61
Vinyl/Aluminum
1/2″ insulation 1.80
Hardboard 1/2″ 0.34
Plywood 5/8” 0.77
     
Roofing    
Asphalt Shingles   0.44
Wood Shingles   0.97
     
Doors    
Metal, insulated 2″ 15.00
Wood, no storm door 1 1/2″ 2.7
Wood, 1″ storm door 1 1/2″ 4.3
Wood, solid core 1 2/3″ 3.1

 

* A number of sources were consulted in the creation of this table: The ASHRAE Handbook of Fundamentals (1997), ColoradoEnergy.org and Guide to Energy Management (2012).

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