Air Barriers

In the IECC, an air barrier is defined as “Material(s) assembled and joined together to provide a barrier to air leakage through the building envelope. An air barrier may be a single material or combination of materials.” The air barrier is an important part of integrated thermal and moisture control in a building. Many air barrier materials or strategies may be employed in a building that meet code requirements, however it is crucial to understand their interactions within the assembly. Below are a variety of resources for choosing code-compliant air barriers. 

Top Resources

This code-compliance report lists a variety of foam sheathing products that can be used to meet IECC energy code air barrier requirements. 

This presentation contains an overview of key building science concepts, U.S. & Canadian code requirements, accepted methods of design to control water vapor, and design solutions for all climate zones and walls with or without continuous insulation.

This guide is a resource for understanding the new air leakage requirements in the 2012 IECC and suggestions on how these new measures can be met. It also provides information from Building America’s Air Sealing Guide, Best Practices and case studies on homes that are currently meeting the provisions. The 2012 IECC and a few International Residential Code (IRC) requirements are referenced throughout the guide.

Best Practices

This Building America Construction Guide for 2x4 wood walls in some of the most populous U.S. climate zones includes a section on air barriers, and explains the relative benefits and drawbacks of different air barrier methods in the context of what water resistive barrier is used. 

A comprehensive assessment of the state-of-the-art of water vapor control for modern, code-compliant, light-frame wall assemblies. 

This guide from the U.S. Department of Housing and Urban Development includes recommended practices for air leakage and water vapor management. It explains how air and moisture management are crucial to integrated building design and includes numerous figures and design examples.