The Bushfire Attack Level (BAL) of your block can have an impact on your home. In areas with high BAL, such as areas of NSW and Vic, BAL requirements can make a significant impact on your home design and the materials used to build with.
The Bushfire Attack Levels are broken down into 6 categories, with different requirements:
BAL Low - minimal effect on design or materials.
BAL 12.5 - some effect on design or materials eg. colorbond roofing required .
BAL 19 - some requirements needed eg. steel flywire.
BAL 29 - additional requirements needed eg. BAL-rated windows, possibly no decking.
BAL 40 - significant requirements needed incl. particular cladding, windows, gutters etc.
BAL Flame Zone - extreme requirements needed including drop-down fire curtains.
People often purchase a block 'cheap' only to find out that the block is BAL 40 or BAL FZ, pushing up the cost of building - in some cases around 50-100%.
BAL assessments can be completed by the owner using fire zone maps provided on their council website or through the local fire station. There are also BAL calculators. In some areas, an independent assessment needs to be conducted by a qualified assessor. Prices range dramatically from $200-300 up to thousands of dollars.
A good starting point is asking council, local fire fighters, SES, or even neighbours.