What is the minimum resting height for concrete masonry units (CMUs) in a composite wall system?

The minimum resting height for concrete masonry units (CMUs) in a composite wall system is established to ensure proper support and stability of the wall assembly. A height of 8 inches allows for adequate load distribution and prevents potential deformation or settling that could occur if the units rest at a lower height.

The design and construction of composite walls involve considerations for weather resistance, load-bearing capacity, and the interactions between different materials. By requiring a minimum height of 8 inches, the code helps to ensure that the integrity and durability of the wall system are maintained over time. This measurement serves as a baseline standard that enhances the structural performance and resilience of the building.

Choosing a lesser height may not provide adequate support, leading to issues such as reduced performance under load or compromised water resistance properties, which is essential in preventing moisture infiltration. Therefore, the specification of 8 inches reflects both engineering best practices and building safety requirements, making it the appropriate answer.