Hempcrete – Fire resistant

In early February 2022, bushfires caused devastation across the south of Western Australia, but proved the fire resistant properties of hempcrete. The hemp-based building material, in the form of hempcrete blocks, survived the blaze.

Environmentally sustainable, mould-resistant and good insulation, the Australian Hemp Council predicts the hemp sector has the potential to be Australia’s next agricultural success story, once red-tape is removed. In March 2022 they pointed to outdated strict regulation which is putting a handbrake on the industrial hemp industry.

An Allied Market Research report from 2020 found the global market worth about $4.9 billion. But in Australia, its farm-gate value is worth just a few million dollars. Due to the social stigma surrounding Cannabis, hemp is often aligned with the illicit plant and incurs ‘guilt by association’. Uses of hemp include, but are not limited to, food, oil, fibre for clothing and material, agricultural products and construction.

Given the severity of the fires that roared through the south of WA, the owner of Hemp Squared had no choice but to flee. However, once the smoke settled, Mr Iggy Van noticed his stock of cured hemp blocks had been largely unaffected by the flames, exhibiting their considerable fire-resistant qualities. “The pallets have burned but the blocks themselves did not, which is a great story for us”, Mr Van said.

Hempcrete blocks are made from hemp hurd, the woody centre of the hemp stalk, along with a combination of other materials including lime and water, and take around eight weeks to fully cure. Mr Van said the knowledge that hemp-based building materials display resistance to fire was not new, but to have seen it demonstrated in a real bushfire scenario was incredibly encouraging. “They get glowing red, you can put your hand on the other side, they’re very well insulated, but the blocks will not burn once they are cured”.

The use of hemp for building dates back centuries, but has not been used until recently in Australia since it was banned early in the 20th century. The Australian Hemp Council echoed the sentiments on hempcrete’s fire-resistant properties. “It’s a perfect material to be using in bushfire-prone areas”. 

Hemp breathes, won’t entertain mould and has proven insulation capacity, whilst absorbing carbon. The primary reason hemp is not regularly used in the building industry is the current cost of production. There is a requirement of significant investment in infrastructure to be able to make the product more economically accessible.

Original source: Bridgetown blaze demonstrates bushfire-resistant benefits of building with hemp


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