A code-required membrane that provides water resistance and air infiltration control in building envelope assemblies.

Weather Resistant Barrier (WRB) is a code-required membrane that provides water resistance and air infiltration control in building envelope assemblies through specialized materials that meet specific performance standards for water resistance, air permeance, and vapor permeability while serving as the primary defense against wind-driven rain and air leakage. This essential building envelope component consists of materials that comply with building code requirements for weather resistance, including housewraps, building papers, liquid-applied membranes, or self-adhering sheets that are installed as continuous barriers behind exterior cladding systems. Weather resistant barriers are critical in modern construction where they provide code-mandated weather protection, control air infiltration, manage moisture movement, and ensure building envelope performance, making them indispensable for residential and commercial construction in climates where weather resistance is required by building codes.

Weather resistant barriers are mandated in various building code applications and climate zones including residential construction where they are required behind most exterior cladding systems, commercial buildings where they provide weather protection for curtain walls and exterior assemblies, high-wind areas where enhanced weather resistance is necessary for storm protection, cold climates where they prevent air infiltration and improve energy efficiency, mixed climates where they manage seasonal moisture variations, and specialty applications including hospitals, schools, and critical facilities where enhanced building envelope performance is required for occupant safety and comfort. Each application requires compliance with specific code requirements, performance standards, and installation methods based on climate zone and building type.

Code requirements and performance standards for WRBs include International Building Code provisions that specify when weather resistant barriers are required, water resistance standards that define minimum performance for wind-driven rain protection, air permeance limits that control air infiltration through building envelopes, vapor permeability requirements that ensure moisture vapor transmission, testing standards including ASTM and AAMA protocols that verify performance characteristics, and installation requirements that specify proper application methods and details. Code compliance ensures adequate weather protection and building performance.

Fun Fact: Weather Resistant Barriers became widely required by building codes in the 1990s following major hurricane damage, and modern WRBs must pass rigorous testing including 6.24 psf water resistance and specific air permeance limits to meet code requirements.

• Weather Barrier
• Air Barrier
• Dust Barrier