Overhang of roof gable causing sagging.

Sagging of roof gable overhang, identified by Peter Weddell, owner/operator of Qld Home Buyers Inspection Service and Queensland Building Inspection Service, QBIS.

Cause of roof gable overhang sagging

I would not recommend this method of supporting a gable overhang in roof construction. As it relies upon the gang nails attached to the outriggers to stop it from sagging. In most cases this alone is insufficient support and causes sagging.

Sagging of gable overhang

The gable overhang extends past the external wall, forming the eaves of a gable end.

Cause of problem:

This sagging gable overhang is due to the outriggers being offset, also the gable overhang extending beyond the external wall being too great.

Sagging of roof gable overhang, with preferred method of construction:

  • The first truss should have been lower.
  • Outriggers extend over the lowered truss as continuous support.
  • A shorter gable overhang beyond the external wall would likely have helped eliminate some sagging.

These suggestions would have greatly reduced the risk of sagging.

This problem would not be picked up by an inspector that is not prepared to get in and on the roof !

Some information that may be of use

Qld Government Roof collapse

Qld Government Technical notes on roofing

For independent Building Inspections Brisbane in all suburbs, Qld Home Buyers Inspection Service. qbis.com.au