Masonry Magazine August 1995 Page. 19
NCMA TEK
National Concrete Masonry Association
a information series from the national authority on concrete masonry technology
TYPICAL SIZES AND SHAPES OF
CONCRETE MASONRY UNITS
**Keywords:** architectural units, bond beams, concrete
brick, dimensions, equivalent thickness, lintels, screen
block, sizes and shapes
INTRODUCTION
Concrete masonry is one of the most versatile building products available because of the wide variety of appearances that can be achieved using concrete masonry units. Concrete masonry units are manufactured in different sizes, shapes, colors, and textures to achieve a number of finishes and functions. In addition, because of its modular nature, different concrete masonry units can be combined within the same wall to achieve variations in texture, pattern, and color.
Certain concrete masonry sizes and shapes are considered standard, while others are popular only in certain regions. Local manufacturers can provide detailed information on specific products, or the feasibility of producing custom units. A more complete guide to concrete masonry units is the Shapes and Sizes Directory (ref. 1).
SIZES
TEK 2-1A
Unit Properties (1995)
Typically, concrete masonry units have nominal face dimensions of 8 in. (203 mm) by 16 in. (406 mm), available in nominal thicknesses of 4 in. (102 mm), 6 in. (152 mm), 8 in. (203 mm), 10 in. (254 mm), and 12 in. (305 mm). Nominal dimensions refer to the module size for planning bond patterns and modular layout with respect to door and window openings. Actual dimensions of concrete masonry units are typically % in. (9.5 mm) less than nominal dimensions, so that the 4 or 8 in. (102 or 203 mm) module is maintained with % in. (9.5 mm) mortar joints. Figure 1 illustrates nominal and actual dimensions for a nominal 8 x 8 x 16 in. (203 x 203 x 406 mm) concrete masonry unit. In addition to these standard
Table 1-Minimum Thickness of Face Shells
and Webs
web thickness,
Web thickness
Equivalent
Face shell
Nominal width
of unit, in. (mm)
3 (76) and 4 (102)
thickness, Webs",
in./linear foot
in. (mm) in. (mm)
(mm/m)
3% (19)
34 (19)
1% (136)
6 (152)
1 (25)
1 (25)
2% (188)
8 (203)
14 (32)
1 (25)
214 (188)
10 (254)
1% (35)
1% (29)
2 (209)
14 (32)
12 (305)
1/2 (38)
1% (29)
2: (209)
14 (32)
"Average of measurements on 3 units taken at the thinnest point
when measured as described in ASTM C 140 (ref. 2). When this
standard is used for split face units, a maximum of 10% of a split
face shell area may have thicknesses less than those shown, but
not less than 4 in. (19 mm). When the units are solid grouted, the
10% limit does not apply.
Sum of the measured thickness of all webs in the unit divided by
the length of the unit. Equivalent web thickness does not apply to
the portion of the unit to be filled with grout. The length of that
portion shall be deducted from the overall length of the unit for
the calculation.
This face shell thickness is applicable where allowable design
load is reduced in proportion to the reduction in thickness from
basic face shell thicknesses shown, except that allowable design
loads on solid grouted units shall not be reduced.