THE RENEWAL OF TRUST IN
RESIDENTIAL CONSTRUCTION
Commission of Inquiry into the Quality of
Condominium Construction in British Columbia
Submitted to the Lieutenant-Governor in Council
Government of British Columbia
by Dave Barrett, Commissioner
June 1998


Chapter Two: The Framework of
Residential Construction
Continued

VI. The Role of the Engineer

The Association of Professional Engineers and Geoscientists (APEGBC) is the association given the authority to regulate the practices of professional engineers and geoscientists, under the Engineers and Geoscientists Act. There are about 18,000 licensed engineers in BC.

The Consulting Engineers of BC (CEBC), is a voluntary association. Half its member firms are involved in building design. Most of these act as sub-consultants to architects in areas of structural, mechanical and, electrical engineering. They also act as registered professionals for coordinating design and review. Several firms are involved in newer, evolving disciplines, such as fire protection, building codes, security systems, and building science. Engineers have also operated as registered professionals on projects which suffer from building envelope problems.

Building science is a relatively new discipline. It works to develop answers to many of the technical questions raised by the problems of leaking condos. Unfortunately, the building design and construction community in BC has been slow to take advantage of this developing expertise. As a result, professional engineers are often not included in the original design of buildings, which eventually experience failed envelopes. They are, however, involved in the remedial activities surrounding investigation and repair.

"While there may be a variety of technical reasons and details that can be identified as the cause of leaking buildings, in our submission the fundamental cause of the leaky condominium problem is that the main participants in the design and construction of these buildings, (owners, designers, builders and regulators) had insufficient awareness of the implications of failing to give due attention to moisture control. Few people appreciated the nature and extent of the problems that were developing. Most relied on conventional local practice for the designs of walls when the architecture was, in hindsight, becoming unconventional and decidedly non local."

John Haythorne, APEGBC

Much of the material presented to the Commission by engineers was of a technical nature. It described, past history, when it was assumed water would enter the building assemblies. Consequently, they were designed to drain the water to the exterior. A drainage capability was provided to prevent the water that inevitably entered from accumulating in the assembly.

" ... historically we've known that all cladding systems leak. Brick leaks. Wood siding leaks. Vinyl siding leaks. Aluminum leaks. Stucco leaks. Stucco has always leaked. That's why you have a drainage plane behind these cladding systems to direct the rain water back to the exterior via a flashing system. It is not possible to build an assembly without holes. It's not possible to seal a building with caulking or sealant or coatings to prevent the rain from entering. The strategy historically has been to drain the rain via a drainage plane.

The reliance on caulking and sealant is something new, something that has only occurred in the last decade or so, certainly in Vancouver, in the Vancouver climate. I have a hypothesis that in a thousand years from now, archaeologists are going to come back and cut Vancouver buildings in half and count the number of layers of caulk to age them. This is not the way to build a building.

Insulation reduces building assembly drying potentials. As we increased insulation levels, we reduced drying potentials; we did not address building wetting potentials. I'm not anti-insulation. I believe passionately in energy conservation. However, this has to be looked at as a balance sheet: where you make an entry on one side of the balance sheet, you must make an entry on the other side. If you're going to reduce drying potentials, you must reduce wetting potentials."

Joe Lstiburek, Engineer

In addition, a number of presenters mentioned that we have a class of materials that do not function like traditional building paper. As a result, building performance has become unpredictable. As well, soaps and additives are typically mixed with stucco to make it more pliable and provide frost protection. However, the additives also make stucco more absorbent. When water leaks through, building paper acts like a blotter.

What appears to be called for is a return to more traditional practices, in which the building has a drainage system and, therefore, can breathe. In terms of remediation, this suggests stripping the cladding of damaged buildings, repairing the structural damage, installing a drainage cavity, and reapplying a cladding system. It is also important in this approach to integrate fully the principles of building science by creating the appropriate air barrier to withstand external load. Removing a cladding that provided an air barrier and replacing it with one that does not, will require accommodation to ensure the renovation performs as expected.

  Recommendation #32: That the APEGBC and AIBC, along with other members of the Advisory Council to the Homeowner Protection Office develop a strategy for identifying building envelopes at risk, develop a set of sound practices for remediation, and distribute the information for use by the industry, strata councils, and homeowners.

  Recommendation #33: That the APEGBC work to establish recognition of Building Envelope Science as an important technical discipline and encourage members who practice in residential construction to upgrade their abilities accordingly.

 

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