North Carolina General Contractors Practice Exam

What are the nominal dimensions of a standard CMU?

1. 8 x 8 x 12

2. 8 x 8 x 16

3. 8 x 10 x 16

4. 8 x 8 x 24

The correct answer is: 8 x 8 x 16

The nominal dimensions of a standard Concrete Masonry Unit (CMU) are 8 inches high, 8 inches wide, and typically 16 inches long. This standard size is prevalent in construction due to its ease of handling and compatibility with various building codes and structural applications. Understanding that the nominal size of the CMU refers to the dimensions before accounting for the mortar joint is crucial. When the mortar is included, the actual dimensions of a standard CMU will be less than the nominal sizes provided. This standardization allows for consistency in construction practices, making it easier for builders and contractors to plan and execute their projects. The other options listed present either incorrect dimensions or dimensions that do not reflect the widely accepted standard size for standard CMUs. Therefore, the recognition of 8 x 8 x 16 as the typical dimensions helps ensure proper communication and understanding in the construction field.