An effectively built wall is designed to control which of the following?

An effectively built wall is designed to control both vapor diffusion and air transportation. This dual function is essential in creating a comfortable and energy-efficient indoor environment.

Vapor diffusion refers to the movement of moisture in its vapor form through building materials. If not properly managed, this can lead to condensation within wall cavities, resulting in mold growth and material degradation. Effective wall assemblies use vapor barriers or permeable materials to regulate this moisture movement and maintain indoor air quality.

Simultaneously, controlling air transportation is crucial as uncontrolled air leaks can significantly impact a building's energy efficiency and comfort. Properly designed walls incorporate measures such as air barriers to reduce unwanted airflow. This control helps prevent drafts and heat loss, keeps conditioned air from escaping, and minimizes the ingress of outside air that may carry moisture.

By addressing both vapor diffusion and air transportation, a well-constructed wall contributes to the overall performance of a building, ensuring it remains dry, energy-efficient, and comfortable for occupants.