Buildings XI Conference -- Why Do Green Building Enclosures Fail and What Can Be Done About It?

Sustainable or "green" buildings are becoming increasingly popular. This is a positive trend, since buildings require the use of vast amounts of resources and energy. They are, among other things, responsible for approximately 39% of CO2 emissions and 65% of waste outputs. Obviously, sustainable buildings require that their enclosure also be conceived and realized according to ecological principles. However, it appears that these green building enclosures are not always durable. Indeed, there are reports in North America of many green buildings having suffered major building enclosure failures after only a few years. This results in environmental, economical, and social impacts that can reduce or negate the positive impacts of those green buildings. The questions then become: What are the potential traps in green building design that can lead to such failures? And what can be done to avoid them? These questions are examined through examples of building enclosure failures in green buildings. These help identify potential pitfalls, which include

• Disregarding building science principles when designing a green building
• Designing green buildings with a configuration that is not adapted to their actual exposure conditions and context
• Using materials in the wrong places and/or for the wrong purposes because they meet certain ecological criteria

A durability plan, such as required in the LEED® Canada Credit MRc8 "Durable Building" (based on CSA Standard S478- 95 [R2001], "Guideline on durability in buildings"), can help minimize the risks of premature failure by addressing durability issues over the whole life cycle of the building. Although this does not guarantee that the building will be durable, it at least ensures that it has been designed and built to be durable. The basic elements of an actual durability plan are presented and discussed. In conclusion, some insights gained through the analysis of failures and the preparation of a durability plan are shared.