Which term is associated with the capacity of a wall to allow moisture passage?

The term that relates to the ability of a wall to allow moisture passage is diffusion. In building materials and construction, diffusion refers to the process by which moisture in the air moves through materials, particularly those that are porous. It is a critical concept in the context of building performance, as moisture that diffuses into walls can impact the integrity and durability of the structure, as well as affect indoor air quality.

Understanding diffusion is essential for home inspectors as it helps to assess moisture management within a building. For example, walls that are designed to be breathable can allow moisture to escape, reducing the risk of mold growth and structural damage. Proper management of moisture through diffusion is a key element in energy efficiency and overall building health.

The other terms, while related to moisture to some degree, describe different processes or phenomena. Retention refers to the ability of a material to hold moisture, transpiration involves the movement of moisture from plants to the atmosphere, and condensation is the process where moisture transitions from a vapor to liquid form, primarily due to temperature changes. Each of these terms addresses different aspects of moisture dynamics, but diffusion specifically defines the capacity of a wall to permit the passage of moisture through it.