Enclosure Design for Cold Climates – Critical Concepts

The design of building enclosures for cold climates poses some special challenges. Key among these is the need to predict and control the flow of vapor and air within or across various enclosure components, which can result in condensation and deterioration. This presentation reviews the theory of moisture migration in the building enclosure and discusses the important and distinct roles of air barriers and vapor retarders – what they are, why they are needed, and how they differ. We review design principles that generate effective barriers for combined air, vapor and heat flow through the building enclosure. Technical and practical limitations of various building materials used as air and vapor barriers are discussed, along with misguided detailing approaches commonly used. Finally, the potential consequences of inadequate enclosure detailing and construction are illustrated through case studies, and the development and implementation of remedial designs are examined.

Learning Objectives
1. Review the mechanisms of moisture migration through building enclosures, and examine enclosure systems that are critical to moisture control.
2. Understand the difference between vapor retarders and air barriers, and how the performance of the enclosure is affected by the HVAC system.
3. Examine the fundamental errors that cause failures, and how to prevent them.
4. Review design principles that generate effective barriers for combined water, air, vapor and heat flow through building enclosures.