Decay Hazard Zone

Geographical areas in Queensland are allocated 1 of 4 levels of timber decay hazard related to rainfall days per year. The areas are rationalised to Local Government Area boundaries.

Geographical areas in Queensland are allocated 1 of 4 levels of timber decay hazard related to rainfall days per year and rationalised to local government boundaries.

Above-ground decay hazard zones are Ag:A, Ag:B, Ag:C, Ag:D
In-ground decay hazard zones are Ig:A; Ig:B, Ig:C, Ig:D. 

Climate is one of the most significant environmental factors affecting the serviceability and performance of construction timbers. Subtropical to tropical climates with periods of warm temperatures and high humidity pose a higher risk of attack by fungal organisms that cause decay than drier climates. See the guide: Decay hazard zones.


Below are a list of values users can choose for this field group.

  • A - Decay hazard zone A; least potential for decay.
  • B - Decay hazard zone B; lower potential than zone C and greater potential than zone A
  • C - Decay hazard zone C; lower decay potential than zone D and greater decay potential than zone B
  • D - Decay hazard zone D; greatest potential for decay.