OBC Part 5: Understanding Durability

OBC Division B, Part 5 requires that “…assemblies exposed to the exterior shall be in accordance with good practice such as described in CSA S478, “Guideline on Durability in Buildings”.

This means architects are responsible for understanding and applying durability concepts to environmental separations (building envelopes or building enclosures) and their structure. Failure to do so can lead to catastrophic losses and massive claims against architects. The “Leaky Condo” crisis in British Columbia in the late 1990s is an example of the widespread economic and social consequences where adherence to the fundamental concept that buildings are required to be durable was ignored by the design professions and construction industry.

The CaGBC offers a LEED credit for “Durability” based on a documented process in accordance with the CSA S478 Guideline, and the Toronto Green Roof Bylaw references the Guideline.

There must be something in this document that can be used by architects to support code compliance and good practice. This program is directed towards understanding what that is.

This program will review the content of CSA S478, Guideline on Durability in Buildings, consider some of the implications impacting architects’ designs and discuss opportunities for architects to reconsider their approach to building envelopes to improve their overall durability.
This program for the OAA is a collaboration between Pro-Demnity Insurance Company and Morrison Hershfield Limited with the objective of enhancing the design services provided by Ontario architects and reducing claims against architects where building envelopes are considered not durable


Session Details

Session ID: 
Thursday, May 25th, 2017: 2:00pm - 5:30pm
3.0 Structured/Core AIA LU HSW
Venue : 
Nova Scotia-Newfoundland

Session Speaker(s)

Brian Sim, Architect AIBC, PP/FRAIC, Hon FAIA, Hon FCARM

Brian Sim is a British Columbia architect with broad experience including extensive review and analysis of building envelope failures widely characterized as “Leaky Condos” or “Leaky Buildings” during the crisis that first became widely known in the mid 1990s. The epidemic of failures and catastrophic losses prompted a withdrawal of professional liability insurers willing to insure BC architects and engineers. The losses continue to be felt as only about half of the impacted buildings have been repaired.  Brian has been deeply involved with both the AIBC and RAIC, serving on AIBC Council, as RAIC President and as Chancellor of the RAIC College of Fellows. He is currently a member of the Canadian Commission on Building and Fire Codes which is the body responsible for the National Building Code in Canada, where he has been a member of the Executive Committee as well as chairing a number of special Task Groups. The Ontario Building Code is derived from the NBC as are all provincial and territorial building codes in Canada. Brian’s broad experience in practice in British Columbia, his service on behalf of the profession, his involvement with the CCBFC and his familiarity with the concepts inherent in durability of buildings makes him particularly well qualified to address this important subject. Brian has been a significant contributor to a number of Pro-Demnity Insurance Company programs including delivery of Loss Prevention Events focused on lessons to be learned from the BC Leaky Condo crisis. 

David Kayll, FMA, P. Eng

Principal, Morrison Hershfield

David Kayll is a principal of Morrison Hershfield and a professional engineer specializing in building science and building envelope, based in the Ottawa office. His main areas of practice include building envelope / enclosure issues, building envelope commissioning, building science analysis and design and facility management consulting for both new and existing facilities. David worked for Morrison Hershfield in the Vancouver office from 1999 to 2003, where he became immersed in the repair of “Leaky Condo” buildings, diagnosing causes of failures and assisting with repair or replacement strategies. From 2003 to the present, David has worked in the Ottawa office covering a broad range of projects including heritage building restoration, new building design, failed building envelope rehabilitation and energy performance evaluation. Projects have ranged from Manitoba to Baffin Island to Newfoundland. He and his colleagues are well respected for their knowledgeable, pragmatic and effective approach to addressing building envelope issues, whether involved in the initial design to achieve Code compliance performance, achievement of the LEED credit for Durability or in assessing failures and recommending repairs. He is a member of the National Building Code’s Standing Committee on Environmental Separation (NBC Part 5) and is actively involved on a number of the Task Groups of the Committee. In addition, David has assisted Pro-Demnity Insurance Company on assignments aimed at assisting architects avoid claims stemming from envelope failure.

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24-27 May 2017
Ottawa, Ontario

About Us

The Royal Architectural Institute of Canada and the Ontario Association of Architects have partnered to present the 2017 Festival of Architecture May 24-27, 2017 in Ottawa.

Join the conversation:


For general information, please contact us at:

  • festival@raic.org 
  • 1-844-856-RAIC ext 200
  • 613-241-3600
  • 330-55 Murray Street, Ottawa, ON K1N 5M3