- Industrial hemp – a cannabis plant with very low concentrations of psychoactive chemical THC – can be used to build houses and has several benefits.
- It’s breathable, good for insulation and can cut down on waste.
- Business Insider Australia reached out to hemp experts to find out what makes it ideal for construction.
- Visit Business Insider Australia’s homepage for more stories.
Hemp is useful for a lot of things, but did you know that it can also be used as a building material?
“Hemp is actually the non-drug version of cannabis,” Professor Rachel Burton, Head of the Food Science Department at The University of Adelaide’s School of Agriculture and Wine told Business Insider Australia.
While there is cannabis the illicit substance, there is also medicinal cannabis for people who may suffer from chronic illnesses and industrial hemp, which can be used for clothing and construction. “It’s all the same plant, it’s just defined by the chemicals it has in it,” she added.
Industrial hemp has a low concentration of tetrahydrocannabinol (THC), the chemical which, at high concentrations, is psychoactive. Depending on the state in Australia, hemp plants must contain less than 1% or 0.3% THC.
Georgina Wilkinson, Vice President of the Australian Industrial Hemp Alliance (AIHA), explained that the major products that come out of industrial hemp are mainly food from the seeds that only account for a small part of the plant. The part inside the stalk – called the hurd – is used for building products while the fibre – outside of the stalk – is used for clothing.
Burton described hemp as a ‘nose to tail’ plant, because all parts of it can be used for different applications.
“There’s a movement now to make use of all the animals. So rather than just using the juicy steaks, you eat the whole animal from nose to tail,” she explained.
“Hemp is a particularly versatile plant because there’s no reason why you couldn’t grow hemp plants where you could take the seed and use that for human food or oil and also use the fibres.
“You can take the fibres away and use them industrially. You may have residue that you can put into biofuels or use it to make bioplastics or compost.”
The stigma around hemp
Hemp Homes Australia‘s Gary Rogers – husband of Georgina Wilkinson – got involved in the industrial hemp industry after taking over the Margaret River Hemp Co store in Western Australia from his in-laws.
Rogers worked in the building industry since he left school and after looking into hempcrete, found that “the shoe fit”, which kicked off his journey into growing hemp crops and processing them. He pointed out that industrial hemp is a billion dollar industry.
“I think the green rush has started,” he told Business Insider Australia. “You’ll see a green rush because everyone wants to jump on the back of getting rich very quick off the cannabis industry.”
Rogers is very passionate about the myriad uses of hemp, from mulch to biofuel to plastics. However, he acknowledged that there is still a stigma attached to it. “It really is a no brainer,” he said. “And that’s something we’ve tried to tell people for 20-odd years: just get over the marijuana stigma.”
Being a builder by trade, Rogers highlighted how “toxic” the industry is in terms of waste, with a large percentage of landfill in Australia consisting of leftover building materials. According to The Conversation, Australia’s construction industry made 20.4 million tons of of waste in 2017, triggered by the growing population and its related property needs.
With the journey he’s on in the hemp homes space, Rogers knows he can make a difference. At the time of the interview, Hemp Homes Australia had built seven homes and was working on its eighth.
Why build a house with hemp?
Burton explained that hemp makes for an ideal building material as its breathable and good for insulation.
Hemp’s insulation capabilities and breathability was also reinforced by Rogers. “Because it breathes, you’re cutting heating and your cooling bill from 50 to 80%,” he said.
When building hemp homes, Rogers doesn’t use paint, reducing toxic smells that can linger with conventionally built homes. Better yet, the company uses 100% of the material.
“Whatever falls on the ground, you can put that back into the next mix,” Rogers said. This reduces the number of skip bins on site and ultimately reduces waste.
There is also an element of sustainability that comes with hemp homes as they can store carbon. “When you when you finish with it [you can] push it back down into the earth,” Rogers said. It makes no carbon because it’s self composting, instead of using your brick, your concrete and everything else – that just becomes landfill. You can’t get rid of that.”
However, Burton added a caveat.
“It means how you grow the plant and if you grow it in an area where you need to put huge amounts of water, chemicals, [etc] then I wouldn’t really call that sustainable,” she said.
Nonetheless, an advantage of hemp is that it doesn’t require excessive amounts of water. “It’s not very water hungry,” Burton said. “It uses less water than other crops for example,” she said, comparing it to wheat and cotton.
Plus, it doesn’t necessarily need pesticides. “There’s not really any pests and diseases that attack industrial hemp plants,” she added. “That may come as we grow more crops and things find it.”
At the end of the day, Rogers said you can’t pit hemp homes against traditional houses.
“You can’t compare them because they’re not apples to apples,” he said. “They are a stand alone home because they offer so much more than your conventional building.”
The future of hemp
With its array of uses, Burton sees even more potential for hemp in the future, from food packaging to bioplastics to renewable fuel.
But for its potential to be fully realised, she believes legislation is needed so that farmers aren’t frightened of growing hemp. A lot of science and breeding would be needed to create crops don’t go over the specific THC limits.
“There’s always this danger at the moment that if [hemp] goes over this level of THC, then the crop has to be destroyed,” Burton said.
Like Burton, Rogers and Wilkinson also support legalisation across the hemp industry.
“If we could manufacture the whole plant here, how many jobs would we generate here?” Wilkinson said, adding that it would be “an absolute game changer.”
Burton was also optimistic about the future of hemp in Australia.
“I think it could go through a real renaissance where people start realising just how useful it is,” Burton said. “I think that’s a very exciting future for hemp.”
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