Air Permeability of Wood Structural Panels as Air Barriers

Building envelope air leakage is a critical concern for energy efficiency, occupant comfort, and moisture control in modern construction. This technical publication addresses common questions about using plywood and oriented strand board (OSB) as air barrier materials, providing code-compliant solutions backed by rigorous research and testing data from ASHRAE-sponsored studies.

This publication is designed for: architects, engineers, designers, builders

The publication presents comprehensive research findings on air permeance values for various wood structural panel products, explains how these materials meet ASHRAE Standard 90.1 requirements, and clarifies the difference between material-level performance and whole-building air leakage. It also provides practical guidance on implementing wood structural panels within complete air barrier systems, including proper sealing methods and integration with water-resistive barriers.

Key sections include:

• Code recognition of wood structural panels as air barriers

• Research basis and test data for air permeance values

• Air movement under pressure conditions

• IECC and energy program requirements

• Common sources of building air leakage

• APA recommendations for implementation

Published by APA — The Engineered Wood Association.