Laverne Dalgleish, Executive Director of ABAA, will be presenting at the CSI National Conference 2026

There is confusion across the US about what is the difference between a vapor barrier and an air barrier. At first glance it should be very simple and that is true if you are only looking at the material. However, if you start to put it in a building, that’s where the confusion starts. The session will cover what are all the barriers, why do they change depending on where they are placed in a building assembly and how they are installed. It will also show that physics does not change no matter the type of building or where it is being built.

Learning Objectives:

• Differentiate among air barriers, vapor barriers, and water-resistive barriers, and explain how each contributes to moisture management, indoor environmental quality, thermal performance, durability, and occupant health and safety within building enclosure systems.
• Analyze how environmental conditions, climate, and building assembly location influence barrier material properties and performance, including their role in controlling condensation, air leakage, and moisture migration that can affect building durability and occupant welfare.
• Critique how installation quality, sequencing, and continuity impact the real-world performance of barrier systems, and identify common failures that may lead to water intrusion, mold growth, energy loss, and compromised building performance.
• Evaluate the performance of barrier materials within different wall and roof assemblies to support resilient, code-compliant, energy-efficient building enclosures that protect occupant health, safety, and welfare.

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