What Is a Parallel Shear Wall?

The Basics

• Shear walls appear commonly in homes and buildings erected in areas that experience high wind or the threat of seismic activity, such as earthquakes. In the context of shear walls, the word “shear” refers to an exterior force that causes the parts of a building to slide parallel to one another. For example, during an earthquake, the shaking motion causes two floors of a building to slide parallel to one another, placing stress on the floors and walls. Builders use shear walls to help alleviate this stress for the health of the building.

How It Works

• Shear walls help relieve stress caused by strong winds or seismic activity by redirecting this stress through weight distribution and absorption. Builders place shear walls inside of the exterior walls of a building, often connecting them to elements like interior walls within a building. When seismic activity or high winds occur, shear walls absorb some of the force of a building’s movement and direct the rest of it to the foundation. Typically the strongest part of any building, the foundation can absorb significantly more stress than any other part of a building before breaking.

In the Wall

• Shear walls are not actually walls, but rather panels that go inside of walls. Builders install numerous shear wall panels throughout a home or building. Each floor of a building gets its own panel installation, as panels typically run the height of a single floor of a building. The number of panels in a building’s walls depends upon the size of each floor and the likelihood of strong winds or seismic activity in the area. Builders typically make shear wall panels from plywood.

Parallel Shear Walls

• Parallel shear walls occur when a builder installs parallel rows of shear wall panels across a straight plane, such as the wall of a building. For instance, if your home contains three shear wall panels lined up parallel to one another, these constitute parallel shear walls. Parallel shear walls usually line up with other sets of parallel shear walls in the floors above and below. However, builders take care not to line these walls up exactly but in a staggered pattern, such that the left half of a shear wall panel on the third floor of a building may overlap with the right half of a panel in the floor below. Staggering panels helps prevent an entire, interconnected set of panels from breaking if one of them gives way.