Straw might seem like the very last product you'd use to make your house fire-resistant.
But as it turns out, straw panels, made from waste material that's otherwise burned off or discarded, are a secret weapon against flames.
When Ross and Cathy Elliot set out to build their house in Wilsons Promontory National Park in Victoria, they knew it'd have to be a design that could withstand ferocious winds and bushfires.
Given they also wanted it to be as sustainable as possible, they went scouting for materials that would tick all the boxes.
Ross and Cathy Elliott's house had to meet strict bushfire ratings. (ABC/Fremantle Media)
"I was looking at ways that we could do it quickly but still quite effectively," Ross said.
"[A friend] explained the benefits of this straw panel and it was just quite incredible — both the acoustics and the ability for it to block all heat and cold from transferring through it at all."
After doing his research, Ross described choosing to use the straw panels for the ceiling in their house as a "no-brainer".
How can straw be fire-resistant?
The key is how it's treated.
After the straw, which is a waste by-product from crops, is harvested, it's processed in a machine that compresses it tightly together.
Derek Layfield owns and runs the factory in Bendigo where Ross and Cathy bought their panels, and has been creating them since the 1970s.
Instead of igniting, the panel becomes charred. (ABC/Fremantle Media)
"There's three elements required to sustain fire; you need fuel, you need ignition and you need oxygen," he said.
"Now if you take one of those elements out of the equation, you don't have fire.
"In our case, our panel is so densely compressed with enormous heat and pressure applied that there's no oxygen there to support combustion."
Instead, when the panel comes into contact with a flame it blocks the heat transfer to the other side and carbonises.
Making use of waste
As well as being a handy way to prevent fire damage and heat or cold transfers (making buildings more energy-friendly), the straw panels also put a waste product to good use.
"It’s the husks from fields of hay that are normally burnt off by farmers," Ross told ABC iview's Grand Designs Australia.
However, according to Victoria's agriculture department, although straw waste — known as wheat stubble — is still burned in some cases, many farmers have moved away from this practice and are now using alternative management techniques.
The panels use straw that's discarded and usually burnt. (ABC/Fremantle Media)
Derek Layfield also pointed out that as well as making use of a waste product, the process of compressing the straw doesn't include any heavy-duty or nasty chemicals.
"The unique thing about this product is that we're working with nature and this is quite important," Derek said.
"Wheat straw, rice straw, the waste material after harvest, has some natural physical properties to it and it makes it self binding.
"It means that our manufacturing process needs no added chemicals, no glues added, no binders of any description to form the panel core.
The straw is compressed into long panels. (ABC/Fremantle Media)
"All we're doing is applying heat and pressure to the straw, the waste material, and under those conditions, with high compression, it will give up a natural polymer ... called lignin ... and that's the material that holds trees together in the environment."
This means the panels are entirely biodegradable and can be redirected from landfill.
But the straw panels aren't without their Achilles heel.
If they get wet, the panels become spongy and useless — as Ross and Cathy nearly found out, with grey clouds and a storm threatening them as they installed their ceiling.
It also means waterproofing is a must.
Ross and Cathy got their ceiling panels installed in the nick of time, before a large storm rolled through. (ABC/Fremantle Media)
Does it cost more?
When it comes to the price tag, both Ross and Derek said straw panels were competitive with other more common materials.
"I don't think, cost-wise, it's any more than other materials," Ross said.
"We put the whole thing up in two days, all the roof, which included the ceiling and sheeting, which was very quick."
Derek said as well as being "cost-effective", the panels are easy to install and are sold as flat-pack studios and granny flats to be used by charities and in disaster zones.
He said one charity in Victoria had been using the flat pack homes to provide extra accommodation for those in need.
"At the end of that building's life, when it's not needed there, it gets returned to a flat pack as a kit and it gets taken away to another family in need.
"Some of those buildings have been rebirthed, coming up to five times now, over [a] 20-year period."
Stream all episodes of the new Grand Designs Australia series on ABC iview or watch tonight on ABC TV at 8pm.