In a wall assembly with brick exterior, sheetrock interior, and insulation between, where should the vapor barrier be placed?

In a wall assembly with brick exterior, sheetrock interior, and insulation between, where should the vapor barrier be placed?

• A. Behind the sheetrock
• B. Behind the brick exterior
• C. Between brick and insulation
• D. On the exterior wall surface

Answer: (A)

The vapor barrier should be placed behind the sheetrock in a wall assembly made of brick on the exterior, sheetrock on the interior, and insulation in between. The primary function of a vapor barrier is to prevent moisture from the interior space from passing through the wall and condensing within the insulation or on the exterior side of the wall, which can lead to mold growth and structural damage. By placing the vapor barrier behind the sheetrock, it effectively inhibits moisture from moving from the warm, humid interior into the colder wall cavity, where it might cool and condense. This location helps maintain a dry insulation layer, improving the thermal performance of the wall assembly. In contrast, placing a vapor barrier behind the brick exterior, between the brick and insulation, or on the exterior wall surface would not be effective for preventing moisture intrusion from the interior environment, as these locations would allow moisture to reach the insulation or concentrated areas in the wall assembly where condensation can occur.

The vapor barrier should be placed behind the sheetrock in a wall assembly made of brick on the exterior, sheetrock on the interior, and insulation in between. The primary function of a vapor barrier is to prevent moisture from the interior space from passing through the wall and condensing within the insulation or on the exterior side of the wall, which can lead to mold growth and structural damage.

By placing the vapor barrier behind the sheetrock, it effectively inhibits moisture from moving from the warm, humid interior into the colder wall cavity, where it might cool and condense. This location helps maintain a dry insulation layer, improving the thermal performance of the wall assembly.

In contrast, placing a vapor barrier behind the brick exterior, between the brick and insulation, or on the exterior wall surface would not be effective for preventing moisture intrusion from the interior environment, as these locations would allow moisture to reach the insulation or concentrated areas in the wall assembly where condensation can occur.