Retrofits

When retrofitting your house, focus on the weakest or most vulnerable elements first.

A building’s bushfire resilience is only as good as its weakest element. Therefore, when thinking about the benefits of retrofitting it is important to understand how extensive the entire list of retrofits that may be required and whether their is sufficient budget to tackle the whole list. It is logically to address the weakest or most vulnerable elements of your house and its surroundings and progressively work through the whole list. The most significant benefit occurs when the last items on the list are addressed. See, Bushfire basics for more information on how to recognise weaknesses and build this list.

It is also a good idea to consider the proximity of your neighbors. If their buildings, vegetation or boundary fencing are close enough to be a threat in a bushfire then it also means that you also may pose a mutual threat to them. If this is the case then it is a good time time to consider the mutual benefits of retrofitting at the same time. Doing this will ultimately make your community more resilient by minimising the risk of house-to-house ignition (see Bushfire risks for more information).

For bushfires, the most vulnerable elements of the house will depend on your specific situation, including the building’s condition and its proximity to vegetation. However, for all buildings (especially those with combustible cladding or framing) gaps in the building’s envelope (e.g., caused by damaged or dislodged; windows, cladding or roofing), and places where debris can accumulate (such as in re-entrant corners) are a major problem. These weaknesses (and others) are vulnerable to surface fires, consequential fires, and ember attack.

It is a good idea to start the retrofit process by learning about the following hazards:

• Embers, surface fires, and consequential fires can occur at any stage of a bushfire, and can ignite and damage buildings even during small, low-severity bushfires. Hence, it is important to mitigate their risks when you retrofit your home.
• Many parts of the house are vulnerable to ember attack, including roof and wall cavities, underfloor spaces, and re-entrant corners.
• Surface fires are low intensity fires that spread along the ground, burning fine fuels such as dry grasses, dry lawn, and leaf litter, or coarser fuels such as wood-chips and bark mulch. These fires have a short flame length, but they are fast moving and can ignite (often from embers) at any time during a bushfire. The coarser fuels like wood-chips and bark mulch can burn for a long time and provide a considerable amount heat to elements of your home.
• Consequential fires (the burning of artificial objects) are common in urban or built-up areas. These fires are caused by the burning of heavy fuel sources, such as cars, boats, wood heaps, fences, decking, sheds, outdoor furniture, rubbish bins, and sporting equipment. Consider relocating these objects away from the house (and other buildings) or ensure that you house is able to withstand the heat exposure from these objects.