Making Transitions: Keeping Air and Water Barriers Continuous  

Building envelopes need to create the four barriers needed as part of any building enclosure, namely water-resistive barriers (WRBs), air barriers (ABs), thermal barriers, and vapor retarders. Commonly, those are each thought of as independent products or systems that are easy to imagine across a smooth continuous plane in a wall or roof deck. However, actual construction isn’t completely smooth and continuous. There are places where different materials and assemblies meet, such as the transition from an above-grade wall to a concrete slab or foundation wall. There are also openings in most walls for windows, doors, and other features, meaning there is a transition of the barriers around those openings. The place where the roof meets the wall, particularly in a commercial building that may have a parapet wall, is another transition area where the continuity of the barriers can be compromised if they are not designed, detailed, and installed correctly. In this course, we will focus on these three transition areas in particular: wall to foundation, openings, and roof to wall. Further, recognizing the innovations and risk mitigation needed in building envelope design, we will also look at the latest advances in all-in-one, integrated gypsum sheathing that include WRB and AB systems during manufacturing as alternatives to field-applied water- and air-barrier systems. These integrated systems have been shown to reduce improper field installations, speed up installation, and save time and money during construction. As such, greater reliability and less risk have been found in using such integrated solutions compared to separate field-applied solutions.

Photo courtesy of Georgia-Pacific Building Products

Peter J. Arsenault, FAIA, NCARB, LEED AP, is a nationally known architect, consultant, continuing education presenter, and prolific author advancing building performance through better design. www.linkedin.com/in/pjaarch, www.pjaarch.com