Bracing connections to top plates at external walls

Issue 49 – May 2013

Clauses 8.7.3.3 and 8.7.3.4 of NZS 3604:2011 Timber-framed buildings cover bracing connections to top plates, both inline and at right angles to external walls.

Inline joints require the following.

  • For inline joints in top plates where the wall contains bracing elements up to 100 bracing units (BU) per metre, the top plate joint requires a minimum of a 3 kN fixing.

  • For inline joints in top plates where the wall contains bracing elements that exceed 100 BU per metre, the top plate joint requires a minimum of a 6 kN fixing.

  • Where the wall contains one or more bracing elements, use the value that is required for the top plate jointing that applies to the highest rating bracing element.

Walls that are at right angles to the external walls require jointing at top plates as follows.

  • Walls that contain bracing elements of not more than 125 BU require at least one fixing of 6 kN capacity to an external wall.

  • Walls that contain bracing elements that exceed 125 BU and up to 250 BU require a minimum of 6 kN connections to two external walls.

  • Walls that contain bracing elements over 250 BU require a minimum of two connections to external walls, each connection to be a minimum of 2.4 kN per 100 BU contained in the wall.

  • The fixings required for walls at right angles, as above, can be directly attached or through framing members in line with the wall, for example, a truss bottom cord or ceiling joist.

Summarised from BRANZ Guideline April 2013.

Published in building.

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