Bushfire Design

Design Factsheet available for Bushfire standard compliant steel roofing system


Construction details are available for a range of COLORBOND® steel clad residential roofing systems designed for use on sites determined to be “Bushfire Attach Level – Flame Zone (BAL-FZ)” under Australian Standard AS3959-2009.

These construction details are contained in BlueScope Steel’s “Fact Sheet: COLORBOND® steel clad roofing system construction, details for bushfire-prone AS3959-2009 BAL-FZ sites”.  This fact sheet has been developed to provide assistance to homeowners, builders and designers who are looking to build or re-build homes on BAL-FZ sites.

Building sites assessed under AS3959-2009 as BAL-FZ are those sites considered to be most at risk of bushfire attack.  In this zone, there is an extremely high risk of ember attack and burning debris ignited by windborne embers, and a likelihood of exposure to an extreme level of radiant heat and direct exposure to flames.  This is an extremely aggressive environment for all building materials, and building systems that perform in this environment can be expensive and complex to install.

This Fact Sheet contains construction details for a range of COLORBOND® steel clad roofing systems, covering various combinations of materials commonly utilized in roof system construction including steel or timber roof trusses, steel or timber fascia and steel roof battens. 

These systems have been assessed by a registered testing authority, Exova Warringtonfire, as being likely to achieve bushfire attack level BAL-FZ if tested in accordance with AS1530.8.2-2007, the required test method under Australian Standard AS3959 for BAL-FZ sites.

Australian Standard AS3959-2009: Construction of buildings in bushfire-prone areas specifies the requirements for the construction of buildings in bushfire-prone areas in order to improve their resistance to bushfire attack from burning embers, radiant heat, flame contact and combinations of the three attack forms.  The objective of the Standard is to provide greater protection for the occupants who may be sheltering in a building while the fire front passes and to increase the chances of the building surviving.

This Fact Sheet relates only to the roofing system requirements of AS3959-2009 and should be used as a guide only. Download Fact Sheet: COLORBOND® steel clad roofing system construction, details for bushfire-prone AS3959-2009 BAL-FZ sites.

For further details regarding the use of BlueScope Steel’s products in the design of buildings located in bushfire zoned areas, please contact

SA / WA / VIC / NT – Scott Nicholson  Ph 08 9365 6679
QLD / NSW / ACT – Michael Waterford Ph  07 3845 9337