Wash. Admin. Code § 51-11C-610211 - Table A102.1 - Default U-factors for ceilings
Table A102.1 Default U-factors for Ceilings
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Standard Frame |
Advanced Frame |
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Ceilings Below Vented Attics |
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Flat |
Baffled |
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R-19 |
0.049 |
0.047 |
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R-30 |
0.036 |
0.032 |
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R-38 |
0.031 |
0.026 |
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R-49 |
0.027 |
0.020 |
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R-60 |
0.025 |
0.017 |
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Scissors Truss |
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R-30 (4/12 roof pitch) |
0.043 |
0.031 |
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R-38 (4/12 roof pitch) |
0.040 |
0.025 |
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R-49 (4/12 roof pitch) |
0.038 |
0.020 |
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R-30 (5/12 roof pitch) |
0.039 |
0.032 |
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R-38 (5/12 roof pitch) |
0.035 |
0.026 |
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R-49 (5/12 roof pitch) |
0.032 |
0.020 |
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Vaulted Ceilings |
16" O.C. |
24" O.C. |
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Vented |
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R-19 2x10 joist |
0.049 |
0.048 |
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R-30 2x12 joist |
0.034 |
0.033 |
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R-38 2x14 joist |
0.027 |
0.027 |
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Unvented |
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R-30 2x10 joist |
0.034 |
0.033 |
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R-38 2x12 joist |
0.029 |
0.027 |
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R-21 + R-21 2x12 joist |
0.026 |
0.025 |
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Roof Deck |
4 x Beams, 48" O.C. |
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R-12.5 |
2" |
Rigid insulation |
0.064 |
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R-21.9 |
3.5" |
Rigid insulation |
0.040 |
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R-37.5 |
6" |
Rigid insulation |
0.025 |
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R-50 |
8" |
Rigid insulation |
0.019 |
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Notes
Statutory Authority: RCW 19.27A.020, 19.27A.025 and chapters 19.27 and 34.05 RCW. 13-04-056, § 51-11C-610211, filed 2/1/13, effective 7/1/13.
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