Roof structure supported by Barap bolts-Kawana Downs, a Western suburb of Brisbane.

Barap bolts supporting a roof structure in Kawana Downs. Courtesy of Peter Weddell, owner/operator of Qld Home Buyers Inspection Service and Qld Home Buyers Inspection Service, qbis 

What are Barap bolts?

  • A metal rod with a thread at each end.
  • Fitted through one or two u shaped bracket located in the middle or a third of distance from the ends
  • Attached by bolts to members of the roof structure.
  • A nut attached to the threaded end of the rod was tightened up, this would place pressure at the mid point where a steel bracket was inserted to support the area required.

What type of roof construction were they used in?

Often in the construction of hand-cut pitched roofs, where support off the internal walls could not be achieved.

Purpose of Barap Bolts:

To allow support of a roof structure where alternate support off an internal wall was not possible.

How they work:

By tightening nuts attached to threads at each end of a rod. This shortens its length and places pressure that allows support, where struts are positioned.

Inadequately supported Barap bolts

Example, with single support.

The photo above shows location of the steel bracket fitted at the mid-way point pushing upward. This is allowing support below the junction of under-purlins and the hip above them.

Inadequately supported Barap bolts

Improperly fitted Barap bolts.

Brackets where attached to the rafters have no support below them, this is causing the ridge-beam to bow sideways.

Roof structure supported by Barap bolts-Kawana Downs

Important notes:

  • Brackets to ends of the Barap bolt must be propped off an appropriate sized beam or off a wall, directly below where they are attached, to avoid downwards pressure caused when the Barap Bolt is tensioned.
  • Otherwise this can (in some circumstances) cause fracturing of the timber (where the bolt is attached) and/or dislodging of the structural member.

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