Wash. Admin. Code § 51-11C-61015 - Section A101.5-Building materials
A1015 Building materials. Default R-values used for building materials shall be as shown in Table A101.5.
Table A101.5
Default R-values for Building Materials
| Material | Nominal Size (in.) | Actual Size (in.) | R-Value (Heat Capacityc) |
| Air cavity (unventilated), between metal studs at 16 inches on centera | - | - | 0.79 |
| Air cavity (unventilated), all other depths and framing materials1 | - | - | 0.91 |
| Airfilm, exterior surfacesb | - | - | 0.17 |
| Airfilm, interior horizontal surfaces, heat flow upb | - | - | 0.61 |
| Airfilm, interior horizontal surfaces, heat flow downb | - | - | 0.92 |
| Airfilm, interior vertical surfacesb | - | - | 0.68 |
| Brick at R-0.12/in. (face brick, 75% solid/25% core area, 130 lbs/ft3) | 4 | 3.5 | 0.32 (5.9) |
| Carpet and rubber pad | - | - | 1.23 |
| Concretec at R-0.0625/in., heavyweight (144 lbs/ft3) | - | 2 | 0.13 (HC-4.8) |
| - | 4 | 0.25 (HC-9.6) | |
| - | 6 | 0.38 (HC-14.4) | |
| - | 8 | 0.50 (HC-19.2) | |
| - | 10 | 0.63 (HC-24.0) | |
| - | 12 | 0.75 (HC-28.8) | |
| Concrete masonry units, solid grouted, lightweight (95 lbs/ft3) | 6 | - | 0.80 (HC-11.4) |
| Concrete masonry units, solid grouted, normal weight (135 lbs/ft3) | 6 | - | 0.51 (HC-13.2) |
| Concrete masonry units, partly grouted, lightweight (95 lbs/ft3) | 6 | - | 1.33 (HC-6.7) |
| Concrete masonry units, partly grouted, normal weight (135 lbs/ft3) | 6 | - | 0.82 (HC-9.0) |
| Concrete masonry units, solid grouted, lightweight (95 lbs/ft3) | 8 | - | 1.05 (HC-15.5) |
| Concrete masonry units, solid grouted, normal weight (135 lbs/ft3) | 8 | - | 0.69 (HC-17.9) |
| Concrete masonry units, partly grouted, lightweight (95 lbs/ft3) | 8 | - | 1.44 (HC-9.6) |
| Concrete masonry units, partly grouted, normal weight (135 lbs/ft3) | 8 | - | 0.98 (HC-12.0) |
| Concrete masonry units, solid grouted, lightweight (95 lbs/ft3) | 10 | - | 1.30 (HC-19.7) |
| Concrete masonry units, solid grouted, normal weight (135 lbs/ft3) | 10 | - | 0.87 (HC-22.6) |
| Concrete masonry units, partly grouted, lightweight (95 lbs/ft3) | 10 | - | 1.61 (HC-11.9) |
| Concrete masonry units, partly grouted, normal weight (135 lbs/ft3) | 10 | - | 1.11 (HC-14.8) |
| Concrete masonry units, solid grouted, lightweight (95 lbs/ft3) | 12 | - | 1.53 (HC-23.9) |
| Concrete masonry units, solid grouted, normal weight (135 lbs/ft3) | 12 | - | 1.06 (HC-27.2) |
| Concrete masonry units, partly grouted, lightweight (95 lbs/ft3) | 12 | - | 1.75 (HC-14.2) |
| Concrete masonry units, partly grouted, normal weight (135 lbs/ft3) | 12 | - | 1.23 (HC-17.5) |
| Flooring, wood subfloor | - | 0.75 | 0.94 |
| Gypsum board | - | 0.5 | 0.45 |
| - | 0.625 | 0.56 | |
| Metal deck | - | - | 0 |
| Roofing, built-up | - | 0.375 | 0.33 |
| Sheathing, vegetable fiber board, 0.78 in. | - | 0.78 | 2.06 |
| Soil at R-0.104/in. | - | 12 | 1.25 |
| Steel, mild | 1 | 0.0031807 | |
| Stucco | - | 0.75 | 0.08 |
a There is no credit for cavities that are open to outside air.
b Air films do not apply to air cavities within an assembly.
c For heat capacity for concrete and concrete masonry materials with densities other than the values listed in Table A101.5, see Tables A103.3.7.1(1) through (3) or Tables A3.1B and A3.1C in ASHRAE/IESNA Standard 90.1.
Notes
Statutory Authority: RCW 19.27A.020, 19.27A.025 and chapters 19.27 and 34.05 RCW. 13-04-056, § 51-11C-61015, filed 2/1/13, effective 7/1/13.
State regulations are updated quarterly; we currently have two versions available. Below is a comparison between our most recent version and the prior quarterly release. More comparison features will be added as we have more versions to compare.