Causes of roof gable overhang to sag.

Learn why sagging of a roof gable overhang occurs and how to alleviate before it develops into a more serious problem. QBIS.

Cause of roof gable overhang sagging

Poor method of supporting a gable overhang causing it to sag.

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 the majority of cases this alone is insufficient support and causes sagging, depending upon depth of the overhang.

Cause of sagging gables:

Gable overhang extends past external wall, forming eaves of a gable end. This sagging gable overhang is due to the outriggers being offset and secured to joints by gang nail plates that twist under the weight of the cantilever. The gable overhang extending beyond the external wall is also too great with weight of roof tiles.

Preferred method of construction to avoid gable sagging:

  • First truss should have been lower than the main roof trusses.
  • Outriggers extend over the lowered truss and beyond the external wall as continuous support.
  • A shorter gable overhang would also likely help eliminate sagging.

These suggestions would have greatly reduced the risk of sagging.