Building in bushfire-prone areas
Keeping your home and family safe from bushfire involves many things. This includes choosing:
- where to build your home on your property
- the materials you use to build
- the design of your house
These can all be factors in defending your home during a bushfire.
Planning SA's website provides an overview of the requirements for all new homes and accommodation facilities built in South Australia's designated Bushfire Prone Areas. It also provides information on extending an existing home in a designated Bushfire Prone Area.
Planning Where to Build Your Home
Many Councils employ a Fire Prevention Officer to assist the community in planning and prevention strategies. They can assist you by:
- Conducting fuel load assessments in your area
- Advising on appropriate fuel management techniques
- Advising on fire prevention issues.
We can also assist you with planning. Contact the Development Assessment Unit on (08) 8391 6077.
Designing your home
When building a new home in a rural area some of the things that you should consider are:
- House siting and design
- Ember proof the house and other buildings
- Metal shutters for windows
- Reserve water supply, pumps, hoses and sprinkler systems
Planning the landscaping around your home will improve your chances of protecting your home during a bushfire. Correctly managed vegetation can provide many benefits during a bushfire including:
- Reducing fire intensity
- Reducing wind speed
- Deflecting and filtering embers
- Providing shelter from radiant heat
Spark proof the house and buildings
To protect your house prevent sparks and burning material from entering through windows, under doors and/or under floorboards. This can be achieved by:
- Fitting metal fly wire mesh or solid screens to spark proof the windows, doors, ventilators and skylights.
- Close in all openings in eaves and under-floor areas.
- Sealing all gaps in the roof area along the ridge cap gutter line and fascia board.
- Extending wall cladding on buildings and sheds to the ground.
- Sealing the flute spaces at the fascia board with fibreglass insulation or scribed flat metal with corrugated iron roofs.
- Tiled roofs require an appropriate fire rated insulation (sarking) immediately below the tiles.
Most homes ignite when sparks or burning embers blow under tiles and start burning roofing timbers or accumulated litter. Metal roofing offers more protection provided it is firmly secured and sealed around vents, skylights, fascias and roof caps.
Underfloor areas that are not enclosed allow sparks and embers to penetrate. If these areas are used to store timber, firewood, or other flammable materials, the risk is increased. Make sure that underfloor areas are kept clear of flammable material during summer.
Windows and vents
Crevices where embers can collect are potential ignition points.
Windows, along verandahs, vents into the house, cracks under doors and window ledges are common places where sparks can get in. You should cover these spots with fine wire mesh to prevent embers from getting into walls, roof cavity areas or through windows.
Another form of active protection for your home are metal shutters. Shutters can be pulled down over exposed windows or placed over skylights in the event of a fire.
- Metal shutters provide protection from radiant heat.
- They prevent windborne debris from shattering glass allowing sparks and embers to enter the building.
- Shutters can be quite expensive so consider installing them on the windows facing the most likely direction of fire.
- Security mesh, metal fly wire and security grade ‘tinting´ are also suitable for protecting windows from windborne debris. These may provide some protection from radiant heat.
- Be aware that although shutters increase your safety they do impede you from observing the progress of the fire once you have retreated inside your house.
- Ordinary blinds used to shade your windows may be an additional fire hazard as these are often made of flammable material and may actually trap sparks and embers.
Reserve water supply
If you rely on electric pumps to obtain your water supply from a bore, dam, swimming pool or overhead tanks under pressure you run the risk of having the power cut-off during a bushfire.
A supplementary water supply under pressure is essential, coupled to a diesel or petrol motor.
Fire water supplies serve three main functions:
- For use by householders to control spot fires and hot spots in and around their properties.
- For protecting the house from radiant heat and sparks using a garden and/or house sprinkler system.
- To supply CFS volunteer fire brigades involved in fighting the main fire.
To operate a sprinkler system you will need an independent water supply with a 22,000 litre capacity.
Make sure you always keep a water supply in reserve for firefighting.
We recommend an overhead water tank fitted with gate valve and canvas hose/coupling or fire tank filler with a 22,000 litre capacity.
Ensure your water supply is close to the house. Do not have exposed areas of plastic pipe or hose that can burn.
Gravity fed water tanks with wide opening outlets will allow you to quickly fill buckets and use your portable pump. Fit gate valves to all new tanks to use your pumping equipment.
Pump and equipment
A 5hp (3.7kw) portable diesel or petrol motor coupled to a 38mm centrifugal fire pump will provide the independent water pressure needed for your emergency firefighting system when mains power is cut.
- Make sure the pump can be operated by any member of the family.
- Check the pump weekly during the Fire Danger Season to be sure it is fuelled and starts readily.
- A key start ignition is ideal.
- Keep the pump in a readily accessible shed in a protected area on the side of the house.
A general purpose petrol engine pump will work efficiently providing it has protection from the radiant heat to prevent fuel vaporization.
A portable water pump will ensure sufficient water pressure during a bushfire emergency.
The pump should have:
- Protective housing to stop fuel vaporization.
- Adequate ventilation for air cooling of the unit.
- An in-line filter to reduce the chance of blockage.
House the pump in a readily accessible shed protected on the side of the house away from the most likely direction of a bushfire.
If you have sufficient water supplies a sprinkler system can be extremely valuable in defending your home against bushfire.
When designing a sprinkler system, be sure to use metal sprinkler heads. Metal pipes are best. If plastic pipes are used they must be installed 40 cm underground so they will not melt. Sprinklers should be positioned so that the water canopy will not blow away in high winds or evaporate.
When planning a sprinkler system remember that fires are accompanied by high winds and high temperatures that can reduce the effectiveness of fine sprays. Keep the sprinklers operating until well after the fire has passed.
Verandahs and balconies can be vulnerable areas of your home with their expanse of timbers open to spark and ember bearing winds.
Sprinklers that spray up towards roofing on verandahs can help save your home. Consider sprinklers placed on the leading edge of guttering so the spray is blown down over the walls and windows and back onto the roof.
Garden sprinkler systems on the windward side can aid your fire prevention effort. Placement around from North to South-West can help retard fire progress towards the house area.
You should consider the following before installing a sprinkler system:
- Will someone be home to turn the sprinklers on in the event of a bushfire? If this condition cannot always be met it may be wiser and cheaper to consider placing more emphasis on passive forms of fire protection like vegetation management and spark and ember proofing.
- Do you have sufficient water to enable a sprinkler system to operate for two to three hours? Reticulated mains water is not always available nor can you rely on it. During a major fire the increased demand may reduce volume and pressure to many houses. We strongly recommend you establish an independent water supply of at least 22,000 L
- Do you have a means of providing adequate water pressure to operate the system? Like mains water a major fire may also cause the electricity supply to fail and on a day of extreme fire danger the power supply will be turned off. Therefore, it is important not to rely on an electric pump to supply pressure. A back up pump driven by a small petrol or diesel motor is essential.
Storage of flammables
Fuel supplies and hazardous chemicals need to be stored in single purpose buildings in cleared areas isolated from other farm buildings.
- Separate and store flammable items away from non-flammable items.
- Store flammable and toxic chemicals, eg. fuel, pesticides and fertilisers etc, downwind of other buildings, especially the home.
- Have all sheds well signed to aid firefighters.
- Consider the general tidiness of your farm buildings. Maintain a tidy layout in all workshops and sheds and ensure an adequate water supply is available for firefighting.
- Store fuel supplies in labelled drums in a well-protected fully enclosed and labelled shed well away from the home area, hay, fodder and machinery sheds.
- For large quantities of flammable fuel consider the use of elevated fuel storage or underground tanks.
- Store chemicals in a separate shed from other flammables, at least 30 metres away from the home with a 4 metre fuel break all around.
- Check relevant legislation to identify restrictions relating to storage of fuel and hazardous chemicals eg:
- Dangerous Substances Act and Regulations, 1979.
- Agricultural Chemicals Act and Regulations, 1955.
- Occupational Health, Safety and Welfare Act, 1988.
A well designed and maintained garden can contribute significantly to your bushfire protection plan. The selection, location and maintenance of plants are an important part of this. The benefits include:
- reducing fire intensity
- reducing wind speed
- deflecting and filtering embers, and
- providing shelter from radiant heat.
Location of vegetation
The following should be considered when planning vegetation for fire protection:
- mown lawn or grazed green grass is most effective near buildings
- use low hazard plants near buildings
- plant low trees and shrubs near buildings, tall plants well away from buildings and power lines
- space trees and shrubs so that there is a break in the line of vegetation from bushland to house
- plant well-watered fruit trees and vegetable gardens on the side of buildings facing the most likely direction of fire.
Maintaining a zone of fuel reduced vegetation around a building is a good fire prevention measure. You need to regularly clean up and remove flammable plant debris before and during the fire danger season. Maintenance tasks include:
- remove trees or prune limbs which overhang the house
- break the path of fire from ground to tree canopy by clearing debris and flammable vegetation under trees and shrubs and by pruning lower branches to provide a vertical 2 metre fire break
- remove accumulated debris in trees and shrubs and prune dead limbs
- retain the moisture content of foliage by watering in the Summer
- grow lawn under trees or keep undergrowth slashed.
Fire retardant plants
Given the right conditions all plants will burn but some plants are more flammable than others.
Planting fire retardant plants and ground cover can:
- absorb more of the heat of the approaching bushfire without burning
- trap embers and sparks
- reduce wind speeds near your house if correctly positioned and maintained
- slow the travel of a fire through the litter layer
- separate the litter layer from the trees above.
Types of vegetation:
Select plants with low flammability characteristics such as fleshy moisture retaining leaves.
- Plants with broad fleshy leaves and/or high salt content burn less readily than those with fine hard leaves.
- Plants with significant amounts of volatile oils, like eucalypts (gums and tea trees) burn readily. These plants should be planted well away from buildings.
- Low growing plants and ground covers are better than shrubs.
- Plants with dense foliage are better than those with open airy crowns.
- Plants that don't retain dead material are better than those that hold up lots of fuel.
- Plants with smooth bark are better than those with stringy or ribbon bark.
A well-designed and maintained windbreak in a rural area will protect buildings from bushfires by:
- Reducing wind speed – when fire winds hit a windbreak they are slowed down and forced up and over the trees, creating a protected area on the leeward side.
- Filtering out flying embers – in a bushfire the greatest risk to any home is sparks blown around in the strong winds, not the flames. Trees may catch many of these sparks before they get to the house. Because green leaves contain water, trees do not usually catch fire from flying embers, although this can happen if there is too much dead material in the trees or on the ground underneath.
- Slowing the spread of the fire – windbreaks slow the wind speed and help slow the spread of fire. They also provide a shield from radiant heat depending on the density of the trees in the windbreak.
Designing windbreaks for the best results:
- plant multiple rows of trees rather than a single row
- plant on the sides of the property most likely to be impacted by fire
- plant an open windbreak that reduces wind speed without causing turbulence.
Other landscaping tips
Position your driveway on the side of your house most likely to be impacted by fire:
- If you plan to build a tennis court or pool also position it between your home and the expected fire direction.
- Build a stone wall, earth mound, hedge or covered fence close to your house as a radiant heat shield.
- If you are on a steep slope terrace, plant your garden with fire retardant species.
- Locate woodpiles away from your house.
All gardeners should be aware that some ornamental plants really take off when they get into the bush. Some do so well they choke out the natives, like blackberries, or become a fire hazard, like gorse.
It's good practice to consult with your local council or the SA Department of Environment, Heritage and Aboriginal Affairs to determine a plant’s suitability for your area.
You can also contact your local Landcare or Bushcare Group (Trees for Life) for information on species that are indigenous to your area. They may even supply plants propagated from seeds collected locally.
For more information see Fact Sheets - Section 4, Preparing your Property