What is wind bracing?
Wind bracing is a system of diagonal members placed in a plane of a building to make that plane rigid. Together with columns and beams, the diagonals form triangles. A triangle cannot change shape unless one of its members gets longer or shorter, whereas a rectangular frame without a diagonal can rack sideways. The Dutch term is windverband.
Why “wind” bracing?
Originally the bracing resisted horizontal wind loads. Today it often provides the overall stability of the structure, including for cantilevers and during construction.
Common types
- Tension rods (cross bracing): slender rods or straps that only work in tension, so they are always fitted in pairs as an X. Wind from one side engages one diagonal, wind from the other side engages the other.
- Compression members: heavier sections that take both tension and compression, so a single diagonal per bay can be enough.
- Diaphragms: well-fixed roof sheathing or wall panels that take over the role of the bracing.
Mistakes to avoid
- Removing diagonals to make room for a window, door or dormer without a replacement. Have a structural engineer check how stability will be provided.
- Slack straps: a strap that is not tight only starts working after the frame has already deformed.
- Weak connections: bracing is only as strong as its end fixings.
Related terms
- Wind brace
- Brace
- Saltire cross brace
- Truss
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