Preparing homes and towns for floods

For those in flood-prone areas, preparing your home for a flood isn’t just smart; it’s essential. Without it, recovering from flood damage can be slow and difficult. But with the right retrofits, and an understanding of flood policy and insurance in Australia, damage can be minimised, and life can return to normal more quickly. Jacinta Cleary and Rachel Goldlust report.

Talk to an engineer or town planner about floods and they’ll ask you what type: riverine, overland, flash or urban flooding from overwhelmed drains and hard surfaces—the list goes on. Flood risks vary around the country depending on topography and climate, with climate change and extreme weather events escalating these risks.

According to the Climate Council’s Climate Risk Map of Australia, floods pose the greatest climate threat to Australian homes. By 2030, riverine flooding is expected to threaten 80% of high-risk properties.

The vast Murray-Darling Basin, spanning significant portions of New South Wales, Victoria and Queensland, places large areas, especially floodplains, under pressure. Regions along the NSW Northern Rivers and the eastern seaboard, including areas around the Brisbane River, the Hawkesbury-Nepean region and the Fitzroy River catchment near Rockhampton, are vulnerable, just to name a few.

Impermeable surfaces like roads and buildings can exacerbate riverine flooding in urban areas. Madeleine Serle still lives upstairs after water flooded the bottom floor of her house in October 2022, when the Maribyrnong River overflowed in the north-western suburbs of Melbourne. Residents describe how the water had nowhere else to go.

Madeleine says she is “one of the fortunate ones” because she has a two-storey home, allowing her to “camp” upstairs with her husband. “Whatever we could save is stacked around me,” highlighting the “enormous emotional load” for her family and the flood-affected community. “I’m just so aware of the psychological trauma that’s all around.” The house has only recently been certified clean and dry “after a spectacularly appalling, ongoing experience with the insurance company,” she says.

Around 600 homes and businesses were flooded, and very few have started rebuilding, with many homeowners citing insurance delays as the cause, limited programs to support the community, and very few experts on the ground. “You walk into a property, you look through the window and it’s all gutted. There’s a social aspect that’s been really difficult. I have people say to me frequently, ‘Oh Madeleine, I wish there had been a bushfire. And then they’d see us.’”

Putting flood resilience to the test
Stories like Madeleine’s are common after floods, with some households displaced for years. On the other hand, people living in homes that have been made flood-resilient might return home within days.

Properties flooded in Brisbane in 2011 faced another test in 2022, but in the interim many homes had been made more flood resilient. In partnership with Brisbane Sustainability Agency (run by Brisbane City Council), architecture practice JDA Co developed Australia’s first Flood Resilient Homes Program (FRHP) to help residents prepare for, endure and recover from flooding. Hundreds of homes were retrofitted.

The 2022 floods showed the work was positive. According to Brisbane City Council, most homes retrofitted under the FRHP withstood major damage during the floods. Surveys of 75 property owners impacted by the floods revealed that 62 owners (83%) found the resilience works successful.

Benefits of the program included reduced insurance premiums, lower repair costs and decreased building material waste. Importantly, some homeowners were able to clean up, dry out and move back in within a few days or weeks, unlike some neighbours who faced rebuilds lasting over 18 months. The FRHP has been succeeded by the Queensland Government’s Resilient Homes Fund (RHF), with JDA Co appointed as the lead technical advisor.

Sam says it’s all been a learning experience, noting that some approaches worked better than others. “The key lesson is not only that there’s less damage, but the disruption that happens to individuals, families and communities can be decreased substantially through retrofitting.”

Retrofit or raise—how to decide?
Sam Bowstead explains there are two common ways to improve the resilience of homes in flood-prone areas, each with its pros and cons. “One is about retrofitting and the other is raising the home,” he says. Queensland’s Resilient Homes Fund offers funding for homeowners to raise, retrofit or even relocate homes to mitigate flood risk. Other states offer varying levels of support for similar initiatives. State governments, councils and community groups often look to Queensland for flood recovery strategies and design.

Builder Tom Yabsley from Evolved Construction, who worked with JDA Co on the FRHP project, says there’s no “silver bullet” when deciding to raise or retrofit. The decision often depends on the expected flood level, which in Queensland can be anything from a few centimetres to a few metres, and the type of house you live in.

“For a house that’s slab on ground and impacted by overland flow where the water comes up and down quite quickly, it’s probably more cost-effective to do a retrofit,” says Tom. “You make it so the water can come through and then you hose it out again. In a situation where you’re going to have water up to your roof, then you would be raising that house,” he says.

Home elevation usually favours timber homes on stumps. Post homes can be jacked up and then a new supporting structure put in underneath “relatively simply,” says Sam. Brick houses generally can’t be raised. Again, the decision comes down to the level of flooding expected. “In some parts of southeast Queensland and northern New South Wales, the water is really deep, so you can only go so high. If you can’t go high enough or your house can’t be raised then retrofitting could be a really good option,” says Sam.

Retrofitting for flood resilience
There are several approaches to making an existing home more flood-resilient, including wet-proofing, dry-proofing and absorption methods. Consulting a building expert to work out the best method is crucial. Sam explains that different typology, landscapes and construction types lend themselves to various resilience measures.

“Building is always complicated and I would advocate getting expert advice for any building work,” he says. “You don’t need an architect for everything, but you need to talk to a builder, building designer or architect to get a technical solution for the house. That’s essential in every home renovation.”

Wet-proofing involves going with the flow, allowing water to come in and then go out again. Designs include flood vents, flood-resistant building materials that are easy to dry, clean or replace, and placing appliances, power points and other electrical systems, both inside and outside the house, above the anticipated floodline. Tom notes that wet-proofing should be considered even for elevated homes.

He describes houses in Lismore that were still inundated during the 2022 Northern Rivers floods despite being elevated. “Letting the water into your house and being able to clean up easily doesn’t appeal to people instantly, but it does cope better with varying flood levels,” he says.

Dry-proofing involves sealing a building to prevent water from entering using flood doors, sealants and membranes. Walls are reinforced to withstand water pressure. While effective for lower levels of flooding, this method has downsides. The structure must be entirely watertight, which can be difficult and costly. High water levels can cause pressure damage to the sealed building, making dry-proofing unsuitable for areas with severe or prolonged flooding.

“If the water goes up over the window line and gets in, then it can’t get out. If you plan for the water to come through, it’s probably the better solution in a lot of cases,” says Tom.

The absorption method treats the whole property as a sponge, allowing water to be slowly absorbed into the ground by increasing permeable surfaces. It can be used alongside wet-proofing.

An example is Steve and Fiona’s house in the Brisbane suburb of Yeronga, featured in issue 60 of Sanctuary magazine. Located near the Brisbane River, the block has an overland flood risk on the bottom third. Stormwater management and landscaping help accommodate the overland flow, including replacing paving with permeable surfaces and planting to reduce stormwater runoff. Overflow from the 22,000-litre rainwater tank is directed to a raingarden in the backyard where it’s filtered and dispersed, and a creek bed was reinstated across the back of the property.

Materials for flood resilience
Retrofitting a home for flood resilience hinges on using materials that won’t disintegrate or go mouldy after a flood, and designing the construction so you can easily clean out every nook and cranny afterwards.

“Walls typically have a cavity between the plasterboard on each side, which can be problematic even if the outside wall lining is resilient, because water will still get trapped,” says Sam. He recommends having one side of the wall that’s removable or, in some cases, just eliminating the cavity altogether. “We’ve done houses with concrete block work, so there’s nowhere for the water to go.”

The materials used to make a home more flood-resilient can be “quite conventional,” Sam explains, such as polished concrete floors or fibre cement sheeting. Using regular products means they are easy to replace when needed. Hardwood timber is better than pine for walls, skirting and architraves because it absorbs less water, doesn’t go mouldy, and can return to its shape if it warps. “These are common materials. They might not be used in every home, but I wouldn’t call them innovative either.”

Tom explains how economical materials were used in the Flood Resilient Homes Program to make homes more flood-resilient, especially in older homes. Fibre cement sheet can be used “like you would in a bathroom” with waterproof membrane to keep water out of the wall cavity, and a skirting tile up to the floodline. “It keeps the budget down because often people won’t have the funds to retrofit their entire downstairs,” says Tom. “When we first suggest it, people might be sceptical, but once it’s done, it looks fine, especially if you’ve got tile or concrete floors.”

Cabinetry and joinery are where newer, innovative materials might be used for flood resilience, especially those used in outdoor kitchens. “You can use these materials for joinery, which, if designed for easy cleaning, could save you from having to rip out your kitchen or your bathroom after a flood,” says Sam. Newer options include composite materials made from a blend of recycled plastics and wood fibres, which offer water resistance and durability. Stainless steel and powder-coated aluminium are other durable options.

While loose-fill insulation will be damaged after a flood due to water absorption, other insulation products can help maintain energy efficiency in your home. Rigid or closed-cell insulation such as extruded foam boards can be water-resistant, with decent R-ratings for thermal comfort. “We just cut it to size and slot it in. It doesn’t suck up any water,” says Tom.

Community support, preparation and recovery
In Maribyrnong, Madeleine Serle says her community sought guidance from bushfire-affected areas and the Bushfire Royal Commission for disaster recovery strategies. “The royal commission highlighted that community recovery must be driven by the community itself. This led to the concept of community-led recovery being incorporated into emergency planning protocols, with local councils responsible for establishing recovery committees.”

Madeleine was the inaugural chair of Maribyrnong Council’s Community Recovery Committee. However, she and other members split from the group when the relationship with council became strained. She now heads the newly-formed Maribyrnong Community Recovery Association (MCRA). Nearly two years after the floods she feels like the recovery process is just beginning, seeking experts and putting forward initiatives to help households recover.

“There’s just so much to do and I now describe myself as a re-engineered flood expert. The scale of social distress is profound. Only about 50% to 60% of the affected area is occupied. There are 1500 people across 600 houses; 80 houses are condemned, and the insurance process for those insured has been an absolute shocker.”

In May 2024 an additional 900 houses near the Maribyrnong River were deemed at risk of flooding, increasing the need for flood-resilient initiatives and retrofits in the area.

Madeleine says MCRA’s community-led recovery process will have three phases. “First is getting homes safe and dry, which involves getting families back, managing insurance issues, and connecting with support services. Next is emergency management, improving warnings, planning and response systems. And then our third phase is mitigation and resilience, which is getting us back together again, not to how it was the day before the flood, but to a resilient future so that when it floods again, we’re prepared.”

She cites a lack of programs and sustainable examples for homeowners to aspire to as holding up progress. “In the UK the insurance companies are required to set aside money from the premiums to fund resilience programs. It’s not a government-only process, the insurance companies have got to step up.”

Madeleine is calling on insurance and property groups to fund a demonstration home and retrofit project in the area. “It’s shocking to see people rebuilding with plaster and everything that is completely wrong. But they’re doing that for understandable reasons. We need support, information and awareness to change this paradigm.”

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