Which walls of a building envelope assembly should not utilize studwell cavities as air plenums?

In a building envelope assembly, outside walls are not suitable for utilizing studwell cavities as air plenums due to the risk of moisture entry and the impact of external environmental conditions. Outside walls are exposed to the elements, which can lead to issues such as condensation, water ingress, and thermal bridging.

Using studwell cavities in outside walls as air plenums could allow air movement that might bring moisture from the exterior into the building's interior environment. This moisture can create a conducive environment for mold growth and can undermine the overall integrity of the building materials. Additionally, outside walls are typically required to maintain a continuous thermal barrier to enhance energy efficiency, which can be compromised by allowing air movement through these cavities.

In contrast, other types of walls, such as interior or partition walls, are better suited for containing air plenums as they are typically within a controlled environment, minimizing the risk of moisture issues. Basement walls often require specific considerations for moisture control but can handle air plenums if properly managed. Overall, maintaining a clear differentiation in how these walls are designed is crucial for ensuring the building's longevity and performance.