Floors and subfloors
Embers and surface fires can ignite subfloors and combustible materials stored in underfloor spaces.
When retrofitting, efforts should be made to prevent flames and embers from entering into subfloors and burning any combustible materials stored in underfloor spaces. Several measures should be considered:
- If possible, fully enclose any raised floors with non-combustible materials.
- Protect (cover) all combustible flooring elements using non-combustible coverings.
- Remove any combustible objects (such as woodheaps and gardening equipment) that have been stored in open underfloor spaces.
Replace combustible enclosures with a fully-enclosed non-combustible alternative
Retrofitting for bushfire protection
The following table contains information on retrofitting a floor system. These measures will provide some protection against most bushfire hazards, however they may not protect against prolonged direct flame contact from burning vegetation or consequential fires.
If you have identified a source of Consequential fire, consider removing or relocating the source or installing a barrier between the house and the source (see Screen plantings). The risk of a consequential fire (e.g., fire spreading from a neighbouring house) is often not economically viable to mitigate. For example, mitigating this risk completely may require drastic changes in building materials and design. As such, it is important to acknowledge the risk of a consequential fire, and include it as a factor in your bushfire survival plan.
Even the most well built home is vulnerable to bushfire if there is a weakness or flaw in the buildings design or maintenance. No home is guaranteed to be 100% bushfire safe.
|Type of floor system||How to protect from fires up to BAL 12.5||How to protect from fires up to BAL 29|
|Concrete slab on the ground||No additional measures are required||No additional measures are required|
|Raised and fully enclosed subfloor||Seal all gaps larger than 2mm||No additional measures are required|
|Install a non-combustible enclosure around any exposed sub-floor spaces|
|Protect vents and weepholes using metal mesh (gaps in the mesh must be no larger than 2mm wide)|
|Raised floor with non-combustible substrate and non-combustible supporting posts and walls (e.g., steel or concrete post)||No additional construction measures are required, however avoid storing combustible objects in open underfloor spaces, if present||No additional measures are required|
|Raised floor with combustible substrate (e.g., timber) and combustible supporting posts and walls||Protect combustible columns, walls and posts using non-combustible materials (see AS 3959:2018 for additional guidance)||No additional measures are required|
|Line timber floors with non-combustible materials|
|Do not store combustible objects in open underfloor spaces, if present|
|If possible, fully enclose the raised floor with a non-combustible enclosure, and seal all gaps that are larger than 2mm|