Moisture Movement in Building Enclosures

Why the Enclosure Leaks Water When it’s Not Raining
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Webinar On-Demand
Sponsored by the Air Barrier Association of America (ABAA)
Presented by Laverne Dalgleish

Learning Objectives:

  1. Determine how moisture moves in the building enclosures.
  2. Identify the top two reasons why moisture shows up in buildings and causes damage.
  3. Discuss why the water vapor transmission rate of materials is overrated.
  4. Identify why moisture problems in buildings will grow and what can be done to manage the risk.


As an IACET Accredited Provider, BNP Media offers IACET CEUs for its learning events that comply with the ANSI/IACET Continuing Education and Training Standard.

Roof leaks and water in wall assemblies are not good for the building. The first reaction is: let’s fix the leak, but then you realize that it is not raining. If there is no rain, you should not get bulk water entry. We overlook the real reason for water in building assemblies because we do not consider all means of moisture transport. Many people then jump to the conclusion that the material used as a water-resistive barrier does not have a high enough perm rating. This presentation will cover all the ways that moisture moves in a building, show why you should not rely on the perm rating of a single material and show you where you could get thousands of gallons of water into the building envelope.


Photo courtesy of the Air Barrier Association of America (ABAA)


Laverne Dalgleish, has been actively involved in the construction industry for over 35 years and has specialized in building envelopes, energy efficiency and building performance for both commercial and residential construction. Over the years, Laverne has become a frequent presenter across North America on a variety of topics as they relate to building envelopes, energy efficiency, green building practices, and standards and quality of construction. He is actively involved in the standards development process and has been involved with International Organization of Standardization for over two decades, traveling the world and developing standards for the building industry. Laverne has also been involved in a number of utility demand side management programs and worked with various government departments across North American such as the U.S Department of Energy, Natural Resources Canada, Environmental Protection Agency, Environment Canada and Canada Mortgage and Housing Corporation.


Air Barrier Association of America The Air Barrier Association of America (ABAA) is a national, not-for-profit trade association comprising a broad cross section of stakeholders in the building enclosure industry. Their membership, which is over 650 member companies, includes manufacturers, architects, engineers, trade contractors, researchers, testing & audit agencies, consultants and building owners. ABAA is the national voice of the air barrier industry and the number one resource for anything to do with air and moisture barriers.


Originally published in December 2022