Hanging beams

Diagram of part of a roof frame showing a ceiling joist and a hanging beam.

A 'hanging beam' is generally a deep timber beam located perpendicular (at right angles or 90ยบ) to ceiling joists and directly above them. The function of a hanging beam is to reduce the span of the ceiling joists. This allows for a more economic joist size and consistent section. Hanging beams must only support ceiling joists and the attached ceiling materials.

The hanging beam has to be adequately supported on its ends over load bearing walls. This is done using blocking pieces of the same timber as the ceiling joists. The ceiling joists are fixed to the hanging beam with:

  • hoop iron straps
  • timber battens
  • or
  • purpose made metal joist hanger brackets.

Hanging beams are held in a vertical position at both ends. They can be nailed or bolted to an available rafter, gable end strut or held by means of angle strutting from internal walls.

The sizes for hanging beams are determined using Table 23 of AS 1684.