Masonry Magazine December 1994 Page. 23
Table 3 - Typical Concrete Masonry Unit Dimensions
| Nominal Unit Size | Actual Unit Size | Faceshell Thickness | Web Thickness |
|---|---|---|---|
| Inch-Pound (in.) | Metric (mm) | Inch-Pound (in.) | Metric (mm) | Inch-Pound (in.) | Metric (mm) | Inch-Pound (in.) | Metric (mm) |
| 4 x 8 x 16 | 102 x 203 x 406 | 3-5/8 x 7-5/8 x 15-5/8 | 92 x 194 x 397 | 3/4 | 19 | 3/4 | 19 |
| 6 x 8 x 16 | 152 x 203 x 406 | 5-5/8 x 7-5/8 x 15-5/8 | 143 x 194 x 397 | 1 | 25 | 1 | 25 |
| 8 x 8 x 16 | 203 x 203 x 406 | 7-5/8 x 7-5/8 x 15-5/8 | 194 x 194 x 397 | 1-1/4 | 32 | 1 | 25 |
| 10 x 8 x 16 | 254 x 203 x 406 | 9-5/8 x 7-5/8 x 15-5/8 | 244 x 194 x 397 | 1-3/8 | 35 | 1-1/8 | 29 |
| 12 x 8 x 16 | 305 x 203 x 406 | 11-5/8 x 7-5/8 x 15-5/8 | 295 x 194 x 397 | 1-1/2 | 38 | 1-1/8 | 29 |
(*) Dimensions are minimums required by ASTM C 90 (ref. 3).
Figure 1 - Soft Metric Equivalents for an 8-inch (8 x 8 x 16) Concrete Masonry Unit
Table 4 - Concrete Masonry Unit Modular Dimensions
| Number of 8-inch modules | Inch-Pound Units | Metric Units |
|---|---|---|
| 1 | 0'-8" | 203 mm |
| 2 | 1'-4" | 406 mm |
| 3 | 2'-0" | 610 mm |
| 4 | 2'-8" | 813 mm |
| 5 | 3'-4" | 1.02 m |
| 6 | 4'-0" | 1.22 m |
| 7 | 4'-8" | 1.42 m |
| 8 | 5'-4" | 1.63 m |
| 9 | 6'-0" | 1.83 m |
| 10 | 6'-8" | 2.03 m |
| 11 | 7"-4" | 2.24 m |
| 12 | 8'-0" | 2.44 m |
| 13 | 8'-8" | 2.64 m |
| 14 | 9'-4" | 2.84 m |
| 15 | 10'-0" | 3.05 m |
| 16 | 10'-8" | 3.25 m |
| 17 | 11'-4" | 3.45 m |
| 18 | 12'-0" | 3.66 m |
| 19 | 12'-8" | 3.86 m |
| 20 | 13'-4" | 4.06 m |
| 21 | 14'-0" | 4.27 m |
| 22 | 14'-8" | 4.47 m |
| 23 | 15'-4" | 4.67 m |
| 24 | 16'-0" | 4.88 m |
| 25 | 16'-8" | 5.08 m |
| 26 | 17'-4" | 5.28 m |
| 27 | 18'-0" | 5.49 m |
| 28 | 18'-8" | 5.69 m |
| 29 | 19'-4" | 5.89 m |
| 30 | 20'-0" | 6.10 m |
MODULAR COORDINATION
Table 4 lists metric equivalents for the 8-inch modules typical of concrete masonry construction. If 4-inch high units are used, wall height can be determined by multiplying the values in Table 4 by 0.5. Similarly, the values can be multiplied by 0.75 to obtain the conversion for 6-inch high units.
The width of an opening in a concrete masonry wall should be a multiple of 8 inches (203 mm) plus the width of one mortar joint (3/8 in. or 10 mm). The height of the opening should be a multiple of 8 inches (203 mm).
For example, a nominal 4' x 4' (1219 x 1219 mm) opening should have actual dimensions of 4'-3/8" x 4' (1229 x 1219 mm).
Similarly, the width of piers should be a multiple of 8 inches (203 mm) minus the width of one mortar joint (3/8 in. or 10 mm).