Entanglement of Vapor Retarders and Air Barriers in Roof Design

Vapor retarders and air barriers – what is the difference? Are we controlling vapor diffusion or air movement? Or both? Air barriers are required for new buildings per the IECC 2015 and IECC 2018, and the importance of air barriers cannot be overstated for energy efficiency and moisture control. We will discuss common vapor retarders and air barriers, how they’re installed, and critical installation details as they relates to the roof and roof/wall interface. A case study with over one million square feet of roofing will be presented to show real-world design and installation considerations and challenges. You’ll also learn that current installation of vapor retarders and air barriers over concrete, steel, and wood decks require different materials and application methods. What’s new, what’s the same, and what to think about when you design roof assemblies in different climate zones and over different types of occupancies with varying construction types.

This course is presented in collaboration with GAF.