Four Barriers for Four Wetting Potentials: How to Design Effective Building Exterior Walls

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Webinar On-Demand
Sponsored by TYPAR
Presented by Len Anastasi

Learning Objectives:

  1. Identify the four wetting potentials that the above grade vertical building enclosure assembly is exposed to.
  2. Determine the four barriers needed to protect the building enclosure assembly from the four wetting potentials.
  3. Explain the basic science and physics of how heat, air and moisture travel through a building enclosure.
  4. Determine how to properly incorporate the four barriers into the building enclosure in order to make it effective.


1 AIA LU/Elective
This test is no longer available for credit

This presentation looks at the four wetting potentials that exterior wall assemblies are exposed to due to the climatic difference between the interior and exterior environment. The four barriers needed to effectively separate the two environments and not create moisture problems are identified. The science and physics behind the inclusion and location of these barriers will be discussed. Various exterior wall assemblies will be reviewed and critiqued. The 2012 and 2015 International Energy Code requirements for insulation exterior wall assemblies will also be reviewed and critiqued. Live hygrothermal analyses will run to show assemblies that work, and assemblies that do not work.

Photo of a wall under construction..

Leonard Anastasi. Len Anastasi has worked in the construction industry for over 30 years in masonry, waterproofing and restoration work. He currently owns EXO-TEC Manufacturing Inc., EXO-TEC Solutions Inc. and EXO-TEC Consulting Inc. He is a member of ASTM’s E06 Committee on Building Performance. He is also a member of the Boston Society of Architects’ Building Enclosure Council. And is the past President of the Air Barrier Association of America and current Director and a Fellow, as well as a member of the Construction Specification Institute and the International Concrete Repair Institute.

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