What is a shear wall?
A shear wall is a stiff wall that resists horizontal forces, such as wind, within its own plane and carries them down to the foundation. Without such walls a building, especially a frame of columns and beams, could rack sideways like a house of cards. Shear walls are usually concrete, calcium silicate blockwork or masonry; in timber frame construction, sheathed walls do the same job. In Dutch it is called a stabiliteitswand.
How a shear wall works
A wall is very stiff along its length and height, but flexible at right angles to its face. That is why shear walls are always placed in two directions, so the building is stable both ways. The floors act as diaphragms: they collect the wind load from the facade and pass it on to the shear walls, which carry it down storey by storey to the foundation.
A shear wall does the same job as a stiff core (stair or lift core) or a bracing system of steel straps or tubes. In a house, the party walls and some internal and external walls often act as shear walls.
Application
- Check the drawings. Structural drawings often mark shear walls separately. If you are unsure, ask a structural engineer.
- No openings without advice. A doorway, duct or wide chase in a shear wall weakens it. Even service chases can matter.
- Don’t demolish during alterations. If a wall has to go, stability must be provided another way, for example with a steel portal frame or bracing. This usually needs calculations and building control approval.
- Good connections. The wall must be properly tied to the floors and foundation, otherwise it cannot pass the forces on.
Common mistake: assuming that a wall that carries no floor has no structural role. A shear wall may carry little weight, yet it keeps the building upright.
Related terms
- Structural stability
- Frame construction
- Load-bearing wall
- Calcium silicate brick
- Structural engineer
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