Click on NCMA evaluation numbers for actual certification reports in Adobe Acrobat (.PDF) format. Right-click (Windows) or Control-Click (Mac OS) on the link to save the file to your computer.
EnerBlock modular block
size with barrier only
and with barrier/grout
at vertical spacing
concrete block density (pcf)
4" thermal barrier
in ungrouted cores
2½" thermal barrier
in ungrouted cores
80
85
95
115
125
135
80
85
95
115
125
135
EnerBlock cross-section
8" cmu with
barrier only
NCMA evaluation no. 06-388-04
NCMA evaluation no. 06-388-03
9.4
8.9
7.9
6.1
5.4
4.7
8.3
7.9
7.1
5.6
5.0
4.4
8" cmu with
barrier and grout:
2" barrier in grouted cores
1¼" barrier in grouted cores
48" on center
8.1
 7.7 6.9 5.4 4.8 4.3 7.2 6.9 6.2 4.9 4.4 3.9
24" on center
7.1
 6.8 6.1 4.9 4.4 3.9 6.4 6.1 5.5 4.4 4.0 3.6
10" cmu with
barrier only
NCMA evaluation no. 06-388-08
NCMA evaluation no. 06-388-07
10.2 9.7 8.7
6.8
6.0
 5.3 8.7 8.3 7.5 6.0 5.4 4.8
10" cmu with
barrier and grout:
2" barrier in grouted cores
1¼" barrier in grouted cores
48" on center
 8.9 8.5 7.6 6.0 5.3 4.7 7.4 7.0 6.4 5.2 4.6 4.2
24" on center
 8.0 7.6 6.8 5.4 4.8 4.3 6.4 6.1 5.6 4.5 4.1 3.7
12" cmu with
barrier only
NCMA evaluation no. 06-388-12
NCMA evaluation no. 06-388-11
10.4
 9.9 9.0 7.2 6.4 5.7 8.9 8.5 7.7
6.3
 5.6
5.1
12" cmu with
barrier and grout:
2" barrier in grouted cores
1¼" barrier in grouted cores
48" on center
 9.1 8.7 7.8 6.3 5.6 5.0 8.6 8.2 7.4 6.0 5.4 4.8
24" on center
 8.2 7.8 7.0 5.6 5.1 4.5 8.3 7.9 7.2 5.8 5.2
4.6
12" cmu with
barrier only
NCMA evaluation no. 06-388-13
10.4 9.9 9.0 7.2 6.4 5.7
12" cmu with
barrier and grout:
2½" barrier in grouted cores
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48" on center
 9.8 9.3 8.4 6.7 6.0 5.3
24" on center
 9.2 8.7 7.9 6.3 5.6 5.0
EnerBlock modular block
size with barrier only
and with barrier/grout
at vertical spacing
concrete block density (pcf)
2" thermal barrier
in ungrouted cores
1¼" thermal barrier
in ungrouted cores
80
85
95
115
125
135
80
85
95
115
125
135
EnerBlock cross-section
8" cmu with
barrier only
 NCMA evaluation no. 06-388-02
NCMA evaluation no. 06-388-01
6.6 6.3 5.7 4.6 4.1 3.7 6.1 5.9 5.3 4.4 4.0 3.6
8" cmu with
barrier and grout:
2" barrier in grouted cores
1¼" barrier in grouted cores
48" on center
 6.5 6.1 5.5 4.5 4.0 3.6 6.0 5.7 5.2 4.2 3.8 3.4
24" on center
 6.3 6.0 5.4 4.3 3.9 3.5 5.9 5.6 5.1 4.2 3.8 3.4
10" cmu with
barrier only
NCMA evaluation no. 06-388-06
NCMA evaluation no. 06-388-05
7.1 6.7 6.1 5.0 4.5 4.1 6.3 6.1 5.6 4.6 4.2 3.8
10" cmu with
barrier and grout:
2" barrier in grouted cores
1¼" barrier in grouted cores
48" on center
 6.8 6.5 5.9 4.8 4.4 3.9 6.2 5.9 5.4 4.5 4.1 3.7
24" on center
 6.7 6.3 5.7 4.7 4.2 3.8 6.0 5.8 5.3 4.4 4.0 3.6
12" cmu with
barrier only
NCMA evaluation no. 06-388-10
NCMA evaluation no. 06-388-09
7.2 6.9 6.3 5.3 4.8
4.3
 6.4 6.2 5.7 4.8 4.4 4.0
12" cmu with
barrier and grout:
2" barrier in grouted cores
1¼" barrier in grouted cores
48" on center
 7.0 6.7 6.1 5.1 4.6 4.2 6.3 6.0 5.5 4.6 4.2 3.9
24" on center
 6.8 6.5 5.9 4.9 4.4 4.0 6.2 5.9 5.4 4.5 4.1 3.8
To convert R-values to U-values: U = 1/R (R = l/U)
  • For integrally insulated masonry, Series-Parallel calculations are the method mandated by the U.S. Department of Energy, most State Energy Codes, The American society of Heating, Refrigeration and Air-Conditioning Engineers, ASHRAE STANDARD 90.1 and the National Concrete Masonry Association (NCMA). The only acceptable alternative is testing according to ASTM C236 "Guarded Hot Box" by an independent accredited laboratory for specific walls, concrete densities and properties. The "NCMA Concrete Masonry R-Value Evaluation" certifies R-values according to the Series-Parallel Calculation Method (Isothermal Planes) or will certify the authenticy of ASTM C236 "Guarded Hot Box" tests. All EnerBlock R-values in Table 1 are as certified by the NCMA Evaluation Program (resistivity high range, assuming protection from moisture). Copies of the Evaluation Certificates are available upon request or as downloadable Adobe Acrobat files (click on the individual links above). All R-values include inside air film (.68) and outside air film (.17) coefficients totaling R=.85.
  • Steady state insulation values should be used in code compliance computer programs such as ENVSTD (ASHRAE 90.1), COMcheck and REScheck. Mass adjustment is built-in for each city in these programs. If the computer programs are not used, adjust for mass according to the International Energy Conservation Code™ (IECC), Table Two.
  • Concrete thermal resistivity values (R per inch) are from NCMA TEK 6-2A, protected from the moisture (resistivity high range).
heating
degree
days
UW & RW required for walls with a heat capacity equal to or exceeding 6.0 BTU/Ft2/ °F
with integal insulation (insulation & mass mixed, such as a log wall)
UW
RW
0.24
4.17
0.22
4.55
0.20
5.00
0.18
5.56
0.16
6.25
0.14
7.14
0.12
8.33
0.10
10.00
0.08
12.50
0.06
16.67
0.04
25.00
0 - 2000
UW
RW
0.33
3.03
0.31
3.23
0.28
3.57
0.25
4.00
0.23
4.35
0.20
5.00
0.17
5.88
0.15
6.67
0.12
8.33
0.09
11.11
0.07
14.29
2001 -
4000
UW
RW
0.32
3.13
0.30
3.33
0.27
3.70
0.24
4.17
0.22
4.55
0.19
5.26
0.17
5.88
0.14
7.14
0.11
9.09
0.09
11.11
0.06
16.67
4001 -
5500
UW
RW
0.30
3.33
0.28
3.57
0.26
3.85
0.23
4.35
0.21
4.76
0.18
5.56
0.16
6.25
0.13
7.69
0.11
9.09
0.08
12.50
0.06
16.67
5501 -
6500
UW
RW
0.28
3.57
0.26
3.85
0.24
4.17
0.21
4.76
0.19
5.26
0.17
5.88
0.14
7.14
0.12
8.33
0.10
10.00
0.08
12.50
0.05
20.00
6501 -
8000
UW
RW
0.26
3.85
0.24
4.17
0.22
4.55
0.20
5.00
0.18
5.56
0.15
6.67
0.13
7.69
0.11
9.09
0.09
11.11
0.07
14.29
0.05
20.00
> 8001
UW
RW
0.24
4.17
0.22
4.55
0.20
5.00
0.18
5.56
0.16
6.25
0.14
7.14
0.12
8.33
0.10
10.00
0.08
12.50
0.06
16.67
0.04
25.00
  • Example (in bold): In Washington, D.C. (4,424 heating degree days), a masonry wall with integral insulation, heat capacity exceeding 6.0 and a U-value of .21 (R=4.8) would be equal to a light-frame wall (heat capacity less than 6.0) with a U-value of .16 (R=6.3).
0 - 2000
Austin, Baton Rouge, Houston, Jacksonville, Los Angeles, Miami, Mobile, New Orleans, Orlando,
Pensacola, Phoenix, San Antonio, San Diego, Savannah, Tucson

2001 - 4000
Atlanta, Birmingham, Charleston (SC), Columbia (SC), Dallas, El Paso, Jackson, Knoxville, Las Vegas,
Little Rock, Los Angeles, Memphis, Nashville, Oklahoma City, Raleigh, Richmond, Sacramento,
San Francisco, Shreveport, St. George, Tulsa

4001 - 5500
Albuquerque, Amarillo, Baltimore, Charleston, Cincinnati, Columbus, Harrisburg, Kansas City, Louisville,
New York City, Newark, Philadelphia, Portland (OR), Pueblo, Seattle, Springfield (MO), St. Louis,
Topeka, Trenton, Washington D.C., Wichita, Wilmington

5501 - 6500
Boise, Boston, Chicago, Cleveland, Colorado Springs, Dayton, Denver, Des Moines, Detroit, Hartford, Indianapolis, Omaha, Pittsburg, Providence, Reno, Salt Lake City, Santa Fe, Springfield (IL), Vancouver

6501 - 8000
Albany, Billings, Buffalo, Burlington, Cheyenne, Concord, Flagstaff, Great Falls (MT), Green Bay,
Kearney, LaCrosse, Madison, Milwaukee, Minneapolis/St. Paul, Montreal, Portland (ME), Rochester (NY),
Sioux City, Sioux Falls, Syracuse, Toronto,

EnerBlock
modular block size
oven-dry concrete block density (pcf)
80
90
100
110
130
135
WT
HC
WT
HC
WT
HC
WT
HC
WT
HC
WT
HC
8 inch
27.6
5.8
30.6
6.4
33.6
7.1
36.6
7.7
42.6
9.4
44.2
9.7
10 inch
29.1
6.1
32.3
6.8
35.4
7.4
38.6
8.1
45.0
9.9
46.5
10.2
12 inch
32.0
6.7
35.6
7.5
39.0
8.2
42.6
8.9
49.6
10.9
51.4
11.3
  • Wall weights as installed, including mortar. Single wythe construction, 8" x 16" concrete masonry units.
  • Heat capacity based on specific heat of concrete, grout and mortar (80 to 120 pcf = .21, -- 120 to
    135 pcf = .22) times the wall weight.
Click on NCMA evaluation numbers for actual certification reports in Adobe Acrobat (.PDF) format. Right-click (Windows) or Control-Click (Mac OS) on the link to save the file to your computer.
EnerBlock
wall construction
ncma
report
number
density
(PCF)
steady-
state
r-value
mass adjusted r-values by heating degree-days
0 -
2000
2001 -
4000
4001 -
5500
5501 -
6500
6501 -
8000
12"x8"x16" cmu with
4" insert
85
95
115
135
9.93
8.96
7.18
5.68
14.9
13.3
10.8
8.1
14.1
12.3
10.1
7.9
13.5
12.2
9.4
7.4
12.3
10.9
8.4
6.8
11.0
9.8
7.8
6.4
12"x8"x16" cmu with
2.5" insert