What is hempcrete and how is it made?

Hempcrete is a sustainable, bio-based building material made from a natural mix of hemp hurd (the woody core of the hemp plant), lime binder, and water. It is commonly used for walls, insulation, floors, and roofs in healthy, low-carbon homes.

Unlike traditional concrete, hempcrete is lightweight, non-toxic, breathable, and carbon-negative. It does not provide structural support on its own; instead, it is typically cast around a timber or steel frame to form highly insulated, high-performance building envelopes.

Hempcrete is a breathable, carbon-storing building material made from hemp and lime, offering a healthier, low-impact alternative to conventional construction.

How hempcrete is made

Hempcrete is produced by combining:

• Hemp hurd – a rapidly renewable agricultural by-product

• Lime binder – often a blend of hydraulic and hydrated lime

• Water – to activate the binding process

Once mixed, the hempcrete is either cast in place, sprayed, or formed into prefabricated blocks or panels. Over time, the lime undergoes a natural process called carbonation, absorbing carbon dioxide from the atmosphere and locking it into the walls for the life of the building.

Why hempcrete is different

Hempcrete walls are:

• Breathable, helping regulate humidity and prevent mould

• Thermally efficient, reducing heating and cooling needs

• Fire, pest, and mould resistant

• Healthier for occupants, with no off-gassing or toxic materials

• Environmentally positive, storing more carbon than is emitted during production

In Australia, hempcrete is increasingly recognised as a future-focused construction solution for homeowners seeking sustainable homes, better indoor air quality, and lower environmental impact.