Home Inspection State Practice Exam

In a cold climate, a vapor retarder should be installed on the side of the wall that faces the conditioned space. This is important because the purpose of a vapor retarder is to prevent moisture from the warm, humid indoor air from passing through the wall assembly and condensing within the wall materials where it could cause damage, such as mold growth or rot.

When warm air from the conditioned space rises or penetrates through the wall, it can reach the colder outer surfaces. If there is moisture on the warm air, it will condense when it meets the cooler surfaces if there is no vapor retarder in place. By placing the vapor retarder on the interior side, it effectively blocks this moisture from entering the wall cavity, allowing the wall to remain dry and maintaining the integrity of the building structure.

In contrast, placing a vapor retarder on the exterior side would allow moisture to remain trapped within the wall, potentially leading to issues in insulation performance and promoting deterioration of building materials. Therefore, for effective moisture management in cold climates, the correct placement of the vapor retarder is crucial, making the response indicating the side facing the conditioned space the most appropriate choice.