Certified Healthcare Constructor (CHC) Practice Exam

The three main components of the exterior wall system that effectively keep moisture out of a building are a weather barrier, an air gap, and exterior finish.

A weather barrier is critical as it prevents water from penetrating the wall system while allowing water vapor to escape. This function is essential in maintaining the integrity of the building materials and providing a dry interior environment. The weather barrier is typically a membrane that is installed in a way that it sheds water away from the wall assembly.

The air gap is another vital component, serving to create a space between the weather barrier and the exterior cladding. This gap helps to prevent moisture buildup, allowing any water that penetrates the exterior finish to drain away effectively. It also assists in ventilating the wall assembly, reducing the risk of mold and other moisture-related issues.

Exterior finish serves as the first line of defense against the elements. It is the visible surface that not only provides aesthetic value but also shields the underlying structures from weather-related damage. By working together, these three components form an effective barrier against moisture intrusion, ensuring the durability and longevity of the building's exterior.

The other options do not encompass the comprehensive functions required to keep moisture out. For example, insulation, vapor barrier, and exterior cladding primarily contribute to