Multi-family buildings in the Lower Mainland of British Columbia and the U.S. Pacific Northwest have come under increasing scrutiny due to the high incidence of water ingress and resulting deterioration of exterior wall assemblies. The fact that the majority of these moisture problems have been related to water ingress has overshadowed other moisture related building enclosure issues. With the recent widespread adoption of rainscreen technology, improved detailing and better quality control, water ingress issues have been reduced significantly, raising the profile of other moisture issues such as condensation control. Current trends in architectural and HVAC design, in combination with changes in building enclosure design to improve water penetration control and energy efficiency often result in increased potential for condensation related moisture problems.
This paper examines these changes through a series of case studies showcasing typical problems that can occur. Innovative monitoring and modeling techniques are also presented that shed new light on the multidisciplinary cause of the problem. Recommendations for integrated architectural and HVAC design to accommodate the more airtight and insulated wall and window assemblies used on buildings today, as well as guidance to occupants and building managers to minimize risk of condensation related moisture problems in exterior wall assemblies is provided. A new test methodology for the investigation and monitoring of condensation problems is also presented.
This paper was presented at the 2010 RCI Building Envelope Symposium.