Bushfire construction requirements

The BCA provides construction requirements for each of the risk categories under lists of each element of construction for homes:

For example, under flooring systems the following construction information is given:

Risk	Requirements
Low risk	No specific construction requirements
Medium risk	a) concrete floors b) suspended concrete floor c) framed floor with all joists and/or bearers not less than 600 mm above finished ground level where: any timber bearers, joists or flooring are of fire retardant material the sub-floor space is fully enclosed with a wall complying with the requirements of this table for an external wall the sub-floor space is fully enclosed with non-combustible sheet material that extends not less than 400 mm above finished ground level and to the bottom of the wall cladding material.
High risk	Same requirements as for medium category
Extreme risk	As for medium risk except that in the case of a framed floor where any bearer or joist is greater than 600 mm above the finished ground level and the floor is not enclosed, the bearers, joists and flooring must be fire retardant treated timber or sheeted underneath with non-combustible material.

Refer to the BCA, Section 3.7.4 Bushfire areas for more information.