Apex Masonry Inc.

Block:

 

Concrete masonry units, commonly known in the building trade as CMU, are 

structural units made with cement and fine aggregate and most often used in 

commercial buildings, retaining walls, fences, planters, etc.  The holes or cells in 

the block are used for the placement of reinforcing steel (rebar) horizontally and 

vertically and then concrete is poured into the cells to create a formidable 

structure.

 

Blocks typically come in several sizes:

6”x8”x16” commonly used for small planters, perimeter fences 6’ high

8”x8”x16” commonly used in commercial buildings

12”x8”x16” sometimes used in commercial buildings where extra support is 

needed and also retaining walls.

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When designating the size of a unit, the width is the first number, then the height, 

and lastly the length.  In the examples above the height and length are all the 

same but the width of the block is the variable according to the building need.  To 

be sure there are other sizes of block but these are the most common.