With climate change literally knocking at our doors and threatening homes across Queensland and northern New South Wales, people are asking how they can future-proof their homes from floods, rising tides and increased rainfall that the recent IPCC report has flagged.
Bushfires and cyclones are often spoken about when it comes to future-proofing homes from Australia’s infamous extreme weather cycle and their rising exacerbation caused by climate inaction.
There are a number of steps that homeowners can take to prevent catastrophic damage to their homes caused by flooding.
First of all: don’t build there
Choose the location of your build carefully. While the price of land in flood-prone areas is usually lower, the flooding and high insurance premiums will cost you more in the long-term.
Sites of high risk are in most cases easily identifiable. There are a bunch of free resources to help you find out if your property is at risk of flooding, or you can pay a professional to assess your property.
For example, Climate Valuation analyses extreme event risk at an address level based on hazards that may be relevant, like flooding, coastal inundation, and forest fire, and looks at resilience of a property and its ability to withstand hazards, and whether climate change may make those risks worsen over time.
Risk Frontiers specialises in the risk management of natural disasters including catastrophe loss modelling and resilience.
The Australian Flood Risk Information Portal amalgamates floods data from different sources into a single online location. It provides access to authoritative flood maps and flood studies, and information about surface water observations from satellite imagery.
Karl Mallon, chief executive officer of Climate Valuation said: “We have a database of the flood risks to every house in Australia. We’ve had thousands of home buyers getting climate risk reports in NSW and QLD. But still lots of people are failing to inform themselves about these escalating climate and extreme weather risks.”
Andrew Gissing, manager of resilience at Risk Frontiers, says that whole communities were predicted to be in the flood path.
“We have an understanding of where high-risk areas are. Bundberg for example is highest, Lismore was on that risk, Grafton, and the Hawkesbury. A number of places impacted have been on the list of highest risk of Australia.
The states with highest risk are Queensland and Victoria,” Andrew explains. “It’s pretty well known that these places are highly at risk of flooding, these communities have a long history of flooding.”
“In general, our models have been very good at identifying suburbs of high risk,” says Karl.
“Places we have warned about for some time, for example parts of Sydney and Brisbane recently flooded. Places we are seeing flooding now are places we consistently warned about… It is disappointing to see the significant financial hardship and dislocation and loss of life in places we know are at risk and that outcomes could have been avoided.”
“We believe many buyers went into the Brisbane market picking up a cheap deal, but they didn’t inform themselves about floods and climate change and that’s going to hurt,” says Andrew.
This comes as a group of Australia’s highest ranking former emergency service chiefs issued a scathing statement on the Morrison government’s failure to prepare for and help alleviate the horrific impacts of the flooding disaster.
Former commissioner of the Queensland Fire & Emergency Services Lee Johnson, a member of Emergency Leaders for Climate Action, said: “We Queenslanders are familiar with floods. We live in Australia’s most disaster-prone state. But the disasters of today are not like the disasters of the past.”
The next step is resilience and adaptations – and the experts say there’s a lot we can do to prepare our homes.
It’s better to implement a combination of these adaptations if your house may be at risk of flooding.
“Forewarned is forearmed,” says Karl, explaining that insurance may be more affordable if resilience adaptations are in place.
- Elevation – rise above the risk. If you must build in a low-lying or flood-risk area, lift your building above the likely height of the flood waters. You can do this by building on stilts or a raised platform, like in the “Queenslander” style of home, or build on a bank of earth or concrete – although this may be less affordable. Queenslander-style homes also have the benefit of passive cooling design through improved airflow and preventing pest infestations that may invade from the ground up. Raising a house requires confidence in the maximum flood level height, and in the house construction that it will bear the force of the floodwaters.
- Dry floodproofing – build your home like an aquarium. Done properly, it is possible to make your building watertight and keep the floodwaters outside of your building. This can be done with sealant, or building in a waterproof membrane. Doors and windows can be flood proofed and utilities raised or sealed. For example, Hafencity in Germany has installed flood proof windows and storm doors for properties on the waterfront. The building needs to withstand the force of the floodwaters, and this kind of design can be a significantly more expensive option.
Dry floodproofing can make a home completely resistant to flooding – if you remember to close your windows.
- Wet floodproofing – build with flood resilient materials. In case floodwaters do manage to enter your home, it’s better to build with materials like polished concrete, tiles or brick that will not be damaged. Carpet tiles are quicker and easier to replace than wall-to-wall carpet or wooden floorboards. Materials like plaster-board, particle board and fibreglass insulation will be ruined by flood, but cement sheeting walls or solid insulation you will be able to scrub clean with a bit of elbow grease. It is important to also move power outlets up the wall and be prepared to say goodbye to any soft furniture that can’t be moved out of the way quickly.
Materials like polished concrete, tiles or brick will not be damaged by floods.
- Floating homes? This may sound a bit futuristic but it is already a traditional style of home in many parts of the world. In an age of climate change, floating houses may be the safest bet if you are in a flood-risk area. Some houses are built on pontoons on the ground and only float in the case of a flood (an amphibious experimental design), or may already be floating on water.
A sustainable floating home design in Amsterdam, Netherlands – part of a new village of 46 floating homes by Space & Matter and i29 architects.
- Install a flood wall. A common technique is to install a perimeter wall around a property with a gate that looks normal, but is a flood gate designed to keep the waters out. The problem with this is that the flood gates displace water to cause more flooding in areas around it – akin to when you sit in a bathtub and the water rises up around you.
Carl Canty from Bubwith, UK, built a flood-proof wall around his property and installed a flood gate.
