Racking

Racking is the sideways (lateral) distortion of a rectangular frame when a horizontal force pushes it out of square, so the frame leans over into a parallelogram. In a building it is driven mainly by wind and earthquake loads acting on the walls and roof.

A bare timber or steel wall frame resists racking poorly: the stud-to-plate joints behave like hinges, so the rectangle can fold. Bracing is what stops it. Diagonal timber, steel strap, or structural sheet bracing (plywood or fibre cement) triangulates the frame and turns the racking force into tension and compression the members can carry.

Under AS 1684, the racking forces on a house are derived from its wind classification, and a bracing schedule sets how much bracing each wall line needs, how it is fixed, and how it ties into the tie-down path. Bracing only works if it is tied down: a braced panel not connected through to the frame and footing cannot resist the load.

Common defect: bracing panels omitted or installed at the wrong spacing, leaving a wall line with less racking resistance than the schedule requires. It is a frame-inspection hold point.

Also known as: racking force, lateral distortion, going out of square.

Related

• Bracing schedule
• Wall bracing
• Timber framing basics
• AS 1684: residential timber-framed construction

See also

• Tie-down
• Wind classification

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Last updated: 2026-05-24. Verified: 2026-05-24. Quarterly review for currency.