The Impact of Permeance on Condensation in Exterior Wall Assemblies
Date: May 26, 2021
Time: 2:00 p.m. - 4:00 p.m. (ET)
Learning Objectives:
- Discuss how vapor permeance is measured using standard test method ASTM E96 and why results obtained from procedure A may not be compared to results obtained from procedure B.
- Explain why a highly permeable water-resistive barrier/air barrier is not as effective in a wall assembly if the vapor diffusion is restricted by other materials of the assembly.
- Understand that for wall assemblies insulated in the stud space only, using water-resistive barriers/air barriers with vapor permeances lower than 5 Perm or higher than 20 Perm increase the risk of condensation and mold growth.
- Describe how for split-insulated wall assemblies, the vapor permeance of the water-resistive barrier/air barrier has little or no impact on the hygrothermal performance of the assembly.
