If It’s Not Raining, Why Is My Roof Leaking?

Roof leaks and moisture within wall assemblies are never good for building performance. The typical response is to search for a rain-related leak—until it becomes clear that it isn’t raining at all. Without rainfall, bulk water entry should not be occurring, yet moisture continues to appear in the building enclosure. Too often, the real causes are overlooked because not all mechanisms of moisture transport are considered. This leads many to incorrectly assume the issue lies with the perm rating of the water-resistive barrier. This presentation examines all primary modes of moisture movement within buildings, explains why relying on the perm rating of a single material is misleading, and reveals how moisture—often in significant volumes—can accumulate within the building envelope.

Learning Objectives:

1. Identify the primary mechanisms of moisture transport in building envelopes
2. Describe the two most common causes of moisture accumulation in buildings
3. Explain why water vapor transmission rate alone is an unreliable indicator of moisture risk
4. Discuss how and why moisture-related building problems tend to worsen over time

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Laverne Dalgleish, Executive Director, ABAA

Mr. Laverne Dalgleish is the Executive Director of the Air Barrier Association of America (ABAA). As such, he works to champion energy conservation in buildings while educating the building owners and designers about the benefits of energy conservation such as durability, comfort, reduced maintenance, reduced HVAC equipment costs and the positive impact on the environment.

Mr. Dalgleish travels North America on a weekly basis to educate building owners and designers on the benefits of effective and working air barrier systems in buildings. This education mission includes working with standards development organizations, training and education groups, government policy departments, and quality assurance program developers for the construction industry. Mr. Dalgleish is the Secretariat of two ISO Committees, ISO TC61 SC10 Cellular Plastics and ISO TC163 SC3 Thermal Insulation Products. He is also Chair of the ULC Thermal Performance in the Building Environment Standards Committee.

Mr. Dalgleish was the key developer of the ABAA Quality Assurance Program for the installation of air barrier systems in buildings. This program is based on ISO9000 and ISO 12576-2 but brings the ISO requirements together with practical applications for the air barrier industry.