A commissionable air barrier system for the building envelope.

Since the mid 70's, the construction industry has made significant advances in energy conservation and improved indoor conditions. These improvements, however, are shadowed  by an increase in building envelope problems to include water penetration, condensation on and in roofs and exterior walls and cladding damages in many of our newer buildings; These problems have been attributed to uncontrolled air leakage. A study of the causes of air leakage through the envelope has revealed that it is not just poor workmanship but a much broader problem, involving inadequate design, the lack of measurable performance indicators, ambiguous regulatory requirements and a general misunderstanding of air and vapour barriers. This report proposes a method to obtain a commissionable air barrier system, by following the steps required to engineer its performance from concept (project brief), through design, construction and building operation. It also proposes a method of monitoring and maintenance for long term durability of the air barrier system. Much of the information for this report was obtained from the ideas and suggestions of the group that participated in the CMHC Workshop on Commissioning the Air Barrier System. Recommendations were made for further research and development work that could accelerate and solidify the process of improving air barrier systems.