Everyone remembers the Black Summer bushfires in Australia. It was just one of the many terrible things that kicked off the terrible year that was 2020 (if you need a reminder, Burning on Amazon Prime is a good documentary to start with).
Bad memories aside, we’re heading into another bushfire season and we can learn a few things from those dark days in 2019-2020.
If you’re living in a bushfire prone area or are planning to build in one, it’s important to know the fire risks and what you can do to minimise them.
To help Aussies prepare for bushfire season, the CSIRO has put together a bushfire best practice guide to answer any and all bushfire-related questions, particularly when it comes to building and renovating your home.
The bushfire best practice guide is thorough and comprehensive, touching on everything from bushfire basics to proper design and maintenance of your home. It helps homeowners address the following areas:
- understanding that bushfires are a natural part of the Australian landscape
- understanding how bushfires interact with homes and gardens
- using principles of design to reduce bushfire risks (including injury and the loss of life)
- improving on existing bushfire regulatory controls
- building or retrofitting a house or garden
While the practice guide is well worth reading in full should you have any bushfire concerns or queries, here are some takeaways we found.
The fire behaviour triangle
According to the report, the intensity and speed at which a bushfire moves depend on three factors: vegetation, weather and terrain.
Which parts of your house are most vulnerable?
Your home might have a high level of risk during a bushfire if it has a high level of vulnerability or a number of weak points. The report outlines these as:
- Any gaps where embers can enter and ignite combustible elements (inside the house, roof cavities, wall cavities, under the house).
- Any corner where embers and debris can accumulate and ignite (including around doors, decks, and window sills).
- Any vertical surface that is exposed to heat, flames or intense ember attack (including windows and combustible walls, eaves, doors, posts and poles).
- Any combustible horizontal surface where ember can accumulate (including decks, roofs and pergolas).
If you’re already in a home that’s situated in a risk area, you might want to consider retrofitting your home to improve its resilience. The CSIRO states in its report:
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.
To help homeowners effectively target these areas, the report has specific sections on roofs, walls, floors, windows, doors, sprinklers and shutters, vents, weep holes and gaps, water, electricity and gas, and ongoing maintenance.
It’s a lot to think about, but it’s worth it.
Don’t forget your lawn
Lawns and yards are a double-edged sword. They can serve as fuel for a bushfire or, if properly maintained, they can serve as effective fire breaks.
The CSIRO outlined some dos and don’ts when it comes to turning your lawn into an effective fire break:
- Choose lawn and grass species that have low flammability characteristics, and which don’t produce a lot of dead plant material. Grass species which remain green throughout the summer are best.
- Keep lawn and grasses short, well-watered and clear of debris. This is very important for grasses under or around trees, shrubs, buildings, and other combustible elements.
- Think strategically about how you can use lawn and cut grasses in the design of your defendable spaces.
- Appropriately dispose of lawn and grass clippings. If possible, dispose of clippings using the green-waste bins provided by your local council.
- Avoid highly flammable lawn and grass species.
- Avoid planting large areas of lawn or cut grasses – add breaks in the vegetation using non-combustible features.
- Manage areas of lawn and cut grasses in a way that doesn’t create an additional fire risk. For example, don’t slash or mow during hot weather and don’t store waste vegetation in large compost piles. Large, dry stacks of waste vegetation are extremely vulnerable to ember and flame attack and can spread fire to other parts of the property.
This is just the tip of the iceberg of all the useful information in the CSIRO’s bushfire guide. It’s well worth a read ahead of bushfire season in order to make sure your home is as prepared as can possibly be.