Depending on your proximity to bushland the bush fire attack level (BAL) of your home may require you to have certain building components installed and the residence constructed to prevent ember attack and the like. The different BAL ratings start at none (there is no increased risk of bush fire attack and end at FZ (the residence is within a fire zone) The cost of building can significantly increase depending on which provisions need to be adopted, given the closeness of the building to bush.
The provisions for a residence in a moderate fire rating (say BAL 19) may extend to having non combustible doors and window frames (for example aluminium or steel in lieu of timber) or the provision of fire shutters to all wall openings.
Regardless of the BAL rating the intention is to close all gaps and reduce the flamability of building components around the home-creating less chance that fire or embers can enter the home or roof space during a bush fire. The sealing of eaves, draft seals below doors, nylon weephole covers, gauze covered vents etc.. are just some examples.
