15th January 2020

As we’ve been recently reminded with the devastating fires of 2019/2020, the Australian bush can be both beautiful and deadly. John Williamson’s famous song, “Home among the gum trees” depicts the great Australian dream of the perfect home. So, how can you be sure that your home is built to withstand a bushfire?

Subsequent to the 2009 Victorian bush fires, the Australian Standards were revised. The “AS3959 – 2009: Construction of buildings in bushfire-prone areas” is the standard that outlines how the  “Bushfire Attack Level” or “BAL” is determined and how a building needs to be constructed.

As you would expect with our Australian Standards, the AS3959 – 2009 is well written and comprehensive. It covers how a site is assessed and given a “Bushfire Attack Level” or “BAL” rating. This will range from BAL-LOW which means there is no requirement for any special construction, through to BAL-12.5, BAL-19, BAL-29 or BAL-40 which denote varying degrees of heat flux exposure and exposure to embers and burning debris. Beyond the BAL-40 rating is also a BAL-FZ which means the building is in a direct flame zone.

Whenever Uniplan is building in a bush setting we most commonly find that BAL-12.5 or BAL-19 construction is required. While there is no easy rule of thumb, you can be quite sure that if there is a tree line or scrub within 100m of your building site you will require at least BAL-12.5 construction. Uniplan will do a thorough review of your site or, if necessary, engage a professional to ascertain the correct BAL rating.

Once the correct BAL rating has been identified, this means Uniplan can ensure the construction methods are perfectly suited to that rating so that your new building meets all the requirements of the Australian Standard AS3959 – 2009.

While this is by no means a detailed and exhaustive list, here is a quick overview of some of the methods we use at Uniplan for the various Bushfire Attack Levels. BAL – FZ, the most extreme rating, has been excluded from the table below as it is not normally achievable in a modular home.

 

BAL – 12.5

BAL – 19

BAL – 29

BAL – 40

Cladding/Walls

Weathertex, fibre-cement or Colorbond cladding

Weathertex, fibre-cement or Colorbond cladding

Fibre-cement or Colorbond cladding

Fibre-cement or Colorbond cladding

Windows/Doors

Protected with aluminium gauze to openings

Toughened glass and protected with aluminium gauze to openings

5mm toughened glass and protected with aluminium gauze to openings

5mm toughened glass and protected with aluminium gauze to entire window

Decking

Hardwood decking

Hardwood decking

Hardwood decking

Non-combustible material

Roofing

Full sarking under steel roof sheets

Full sarking under steel roof sheets

Full sarking under steel roof sheets

Full sarking under steel roof sheets

 

NOTE: This is not intended as a comprehensive list of all requirements but merely as an indication of some common building elements.

In summary, there are two things ensure when planning to build in a bushfire prone area:

  1. Don’t take any shortcuts on having your land evaluated to establish the correct Bushfire Attack Level. You would rather be safe than sorry.
  2. Make sure you choose a builder, like Uniplan, that fully understands the requirements of the construction methods required. Any shortcuts during construction could have catastrophic results if a dreaded bushfire should surround your home.

For more information, reach out to one of our helpful team today. We’re here to make your building journey easy.  

 

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