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AGENDA

11:45 - 12:00  Registration & Housekeeping

12:00 - 12:30  Lunch

12:30 -   1:30  Presentation and Q&A

 1:30  -   2:00  Networking (optional)

ABOUT THE PRESENTER

Hamid Heidarali, P.Eng
Hamid Design Build

Hamid Heidarali is a Building Science specialist at HDB with a strong passion for high performance buildings that minimize their impact on the environment, while providing superior experience for occupants. He has been providing Building Science engineering on a wide range of projects in Canada over the past two decades. Hamid taught building envelope courses to Masters students at British Columbia Institute of Technology (BCIT) from 2015 till 2020, and offers holistic building envelope workshops for the construction professionals on a regular basis.

ABOUT THE TOPIC
Avoiding Double Vapour Barriers: A Fundamental Principle Overshadowed in Some Current Design Practices

Avoiding double vapour barriers in building envelope assemblies is among the foundational principles of building science. This guidance was reinforced for decades through the education and research conducted by the Division of Building Research at the National Research Council of Canada throughout the 1960s, 70s, and 80s, and captured in publications such as the Canadian Building Digests and reference texts like Building Science for a Cold Climate. This fundamental has long been embedded in Canadian Building Code provisions and remains central to durable, predictable building‑envelope performance.

While this topic received significant attention historically, recent years have seen the introduction of various assemblies—often configured to meet energy‑efficiency targets—that create double‑vapour‑barrier conditions. In many cases, these configurations have led to performance failures, compromised long‑term durability, and nuisance conditions for end users. Forensic reviews confirm that these outcomes are not attributed solely to construction error; rather, in many cases, the underlying issues stem from design decisions.

This session revisits the principle of avoiding double vapour barriers by examining its historical context, highlighting why this “old wisdom” remains crucial for long‑term durability, and reviewing how it should continue to inform design decisions. Using case studies supported by photos, videos, and field documentation, the session will illustrate where design choices have disregarded this principle and will provide practical and holistic takeaways to support performance, durability, and end‑user experience.

REGISTRATION

Please Note:
All WALK-UPS (non pre-registered attendees) must pay a blanket price of $65.00, including Students and Members.

Refunds:
No Refunds after Friday, Sept. 11th Noon. Refunds will be offered before Sept. 11th less $25 admin charge.

Education Credits:
This luncheon seminar qualifies for 1.0 AIBC Core Learning Unit. To receive credit, enter a valid AIBC Registration Number during the online registration process.