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 RValue 
Mass Wall 
Floor 
Basement ^{c} Wall 
Slab ^{d} RValue & Depth 
Crawl Space Wall 


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+5^{h} 
20 or 13+5ci or 0+15 
5/8 
8/13 
19 
19 
5/13^{f} 
5/13^{f} 
5ci or 13^{f}

0 
0 
10ci, 2ft 
5/13 
5/13 
5ci or 13^{f} 
4 except Marine 
38 
49 
60 
13 
20 or 13+5^{h} 
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+5^{h} 
20 or 13+5^{h} 
30 or 20+5ci or 13+10ci or 0+20ci 
13/17 
13/17 
30^{g} 
30^{g} 
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+5^{h} 
20+5^{h} or 13+10^{h} 
30 or 20+5ci or 13+10ci or 0+20ci 
15/19 
15/20 
30^{g} 
30^{g} 
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+5^{h} or 13+10^{h} 
30 or 20+5ci or 13+10ci or 0+20ci 
19/21 
19/21 
38^{g}* IRC: 30^{g} 
38^{g} 
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: Rvalues are minimums. R19 batts compressed into a nominal 2x6 framing cavity such that the Rvalue is reduced by R1 or more shall be marked with the compressed batt Rvalue in addition to the full thickness Rvalue.
20092018 IECC: “10/13” means R10 continuous insulation (called “insulated sheathing” in 2009 IECC) on the interior or exterior of the home or R13 cavity insulation at the interior of the basement wall. “15/19” means R15 continuous insulation on the interior or exterior of the home or R19 cavity insulation at the interior of the basement wall. Alternatively, compliance with “15/19” shall be R13 cavity insulation on the interior of the basement wall plus R5 continuous insulation on the interior or exterior of the home. 2009 IRC Only: The first Rvalue applies to continuous insulation, the second to framing cavity insulation; either insulation meets the requirement.
