Which materials are considered vapor impermeable?

Vapor impermeable materials are those that do not allow water vapor to pass through them, which is critical in certain construction applications to prevent moisture accumulation that can lead to mold, rot, and building deterioration. Polyethylene and foil sheeting are excellent examples of vapor impermeable materials, as they are specifically manufactured to resist the transmission of moisture.

Polyethylene sheeting, often referred to as vapor barrier, is widely used in construction underneath concrete slabs or in walls to protect the building structure from moisture ingress. Similarly, foil sheeting reflects moisture and also blocks vapor transfer, further reinforcing its role as a vapor barrier.

Other materials listed in the choices do not exhibit the same level of resistance to vapor. For example, brick is porous and allows moisture to pass through, while wood is also a natural material that can absorb moisture from the environment. Most house wrap materials are designed to allow some degree of moisture vapor to escape while preventing liquid water from entering; this property makes them less than completely vapor impermeable. Hence, they are used for managing moisture while allowing some breathability in the walls, which is beneficial for preventing vapor buildup.

In conclusion, the characteristics of polyethylene and foil sheeting as designed vapor barriers make them the correct answer regarding materials that