This table is adapted from Table R402.1.1 in the 2009 and 2012 International Energy Conservation Code (IECC), which is Table R402.1.2 in the 2015 and 2018 IECC, and Table R402.1.3 in the 2021 IECC, as well as Table N1102.1 in the 2009 International Residential Code (IRC), Table 1102.1.1 in the 2012 IRC, Table N1102.1.2 in the 2015 and 2018 IRC, and Table N1102.1.3 in the 2021 IRC.
Ceiling |
Wood Frame Wall R-Value |
Mass Wall |
Floor |
Basement c Wall |
Slab d R-Value & Depth |
Crawl Space Wall |
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|
2009 IECC |
2012 2018 IECC |
2021 IECC |
2009 IECC |
2012 2018 IECC |
2021 IECC h |
2009 IECC k |
2012 2018 2021 IECC |
2009 IECC |
2012 2018 2021 IECC |
2009 IECC |
2012 2018 IECC |
2021 IECC |
2009 IECC |
2012 2018 IECC |
2021 IECC |
2009 IECC |
2012 2018 IECC |
2021 IECC |
1 |
30 |
30 |
30 |
13 |
13 |
13 or 0+10ci |
3/4 |
3/4 |
13 |
13 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
2 |
30 |
38 |
49 |
13 |
13 |
13 or 0+10ci |
4/6 |
4/6 |
13 |
13 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
3 |
30 |
38 |
49 |
13 |
20 or 13+5h |
20 or 13+5ci or 0+15 |
5/8 |
8/13 |
19 |
19 |
5/13f |
5/13f |
5ci or 13f
|
0 |
0 |
10ci, 2ft |
5/13 |
5/13 |
5ci or 13f |
4 except Marine |
38 |
49 |
60 |
13 |
20 or 13+5h |
30 or 20+5ci or 13+10ci or 0+20ci |
5/10 |
8/13 |
19 |
19 |
10/13 |
10/13 |
10ci or 13 |
10, |
10, |
10ci, 4ft |
10/13 |
10/13 |
10ci or 13 |
5 and Marine 4 |
38 |
49 |
60 |
20 or 13+5h |
20 or 13+5h |
30 or 20+5ci or 13+10ci or 0+20ci |
13/17 |
13/17 |
30g |
30g |
10/13 |
15/19 |
15ci or 19 or 13+5ci |
10, |
10, |
10ci, 4ft |
10/13 |
15/19 |
15ci or 19 or 13+5ci |
6 |
49 |
49 |
60 |
20 or 13+5h |
20+5h or 13+10h |
30 or 20+5ci or 13+10ci or 0+20ci |
15/19 |
15/20 |
30g |
30g |
15/19* |
15/19 |
15ci or 19 or 13+5ci |
10, |
10, |
10ci, 4ft |
10/13 |
15/19 |
15ci or 19 or 13+5ci |
7 and 8 |
49 |
49 |
60 |
21 |
20+5h or 13+10h |
30 or 20+5ci or 13+10ci or 0+20ci |
19/21 |
19/21 |
38g* IRC: 30g |
38g |
15/19* IRC: 10/13 |
15/19 |
15ci or 19 or 13+5ci |
10, |
10, |
10ci, 4ft |
10/13 |
15/19 |
15ci or 19 or 13+5ci |
For SI: 1 foot = 304.8 mm. NR = not required. Ci = continuous insulation. *The IRC code requirement differs from the IECC code requirement, as noted.
2009 IECC: R-values are minimums. R-19 batts compressed into a nominal 2x6 framing cavity such that the R-value is reduced by R-1 or more shall be marked with the compressed batt R-value in addition to the full thickness R-value.
2009-2018 IECC: “10/13” means R-10 continuous insulation (called “insulated sheathing” in 2009 IECC) on the interior or exterior of the home or R-13 cavity insulation at the interior of the basement wall. “15/19” means R-15 continuous insulation on the interior or exterior of the home or R-19 cavity insulation at the interior of the basement wall. Alternatively, compliance with “15/19” shall be R-13 cavity insulation on the interior of the basement wall plus R-5 continuous insulation on the interior or exterior of the home. 2009 IRC Only: The first R-value applies to continuous insulation, the second to framing cavity insulation; either insulation meets the requirement.
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