The structures that hold up our buildings are not infinitely rigid. Instead, building structures are intentionally designed to undergo a limited amount of movement under wind loads, live loads, seismic loads, and other forces. The magnitude of this movement can often be fairly small (in the order of several inches). However, even small movements can affect continuity in the building structure unless the design accounts for them.
Therefore, when one is maintaining the performance of a continuous air- and water-control layer, it is important to consider the impact of structural movements on the building enclosure. In particular, the movement of building structures has unique implications for panelized enclosure systems that are designed to move along with the structure. This article focuses on the deflection and interstory drift considerations of panelized framed wall systems. Other types of movement from sources such as thermal movement, creep, and column shortening are outside the scope of this article but should be considered in design as well.