What are "weather resistant barriers" in roofing?

Weather resistant barriers in roofing play a crucial role in protecting the building's interior from moisture while simultaneously allowing moisture vapor to escape. This function is essential for maintaining a healthy building envelope. The primary purpose of these barriers is to prevent water infiltration caused by rain, snow, or ice, which can lead to significant damage, mold growth, and deterioration of structural components over time.

These materials, which can include house wrap, underlayment, or foam sheets, are designed to repel water while allowing moisture vapor from the interior to bypass them. This vapor permeability is critical as it helps to prevent condensation within the wall assembly, addressing both water intrusion and moisture management.

Understanding the function of weather resistant barriers highlights their importance in roofing systems, ensuring both durability and comfort within the structure.