What installation failure is most likely to cause racking in a wall structure?

The most significant factor contributing to racking in a wall structure is the failure to install wall bracing. Wall bracing provides the necessary support to resist lateral forces caused by wind or seismic activity. When walls lack adequate bracing, they can become unstable, allowing them to move or rack, which means they can deform or lean out of the vertical plane. This movement can lead to structural damage and compromise the integrity of the building.

While improperly installed insulation, inadequate floor joist support, and incorrect wall stud spacing can affect a building's overall performance and comfort, they do not directly cause the wall to rack in the same manner or to the same extent as the absence of wall bracing does. Therefore, wall bracing is critical for maintaining the structural rigidity and safety of wall systems under various loads.