Cannabis Construction with Hemp Concrete

Current construction methods use materials that are not sustainable, add to the CO2 crisis, and also require toxic chemicals to produce.

What if there was a material that grew from a renewable resource that was grown without chemical fertilizers, pesticides, or herbicides? What if it could be produced without using any toxic chemicals, and actually absorbed CO2 out of the atmosphere?

Those properties alone should make Hemp concrete construction worth considering, but it get’s even better!
Hemp concrete (also called Hempcrete or Hemplime) is a bio-based building material composed of the woody core of industrial hemp (called hurds or shivs) combined with a lime based binder. No other natural fiber is able to bond so well with lime as hemp hurds do. That’s due to the high amounts of silica they contain, as well as their unique structure. The result is hemp concrete  – a lightweight insulating material ideal for most climates since it combines insulation with thermal mass.

Using Cannabis construction methods, Hemp concrete could replace:

  • Fiberglass insulation
  • Drywall/gyprock
  • Bricks & concrete
  • Moisture barriers

All of this for a product that is actually Carbon Negative – that’s right, it removes CO2 from the air around it. This doesn’t just occur when it is growing in the fields, but also for nearly 100 years after first mixing the hemp hurds with lime. Slowly, through the process of carbonization, the Hemp concrete turns into limestone while petrifying any nearby wood framing.

Surprisingly, this isn’t a brittle structure. The hemp fibers are extremely elastic, and don’t appear to crack and crumble during an earthquake, although more research is needed. In England, some insurers actually provide a discount for hempcrete construction because of its durability.

Additional Benefits of Cannabis Construction with Hemp Concrete:

Based on analysis of 40 Hemp concrete buildings, the insulation properties of cannabis construction materials actually go off the chart of conventional thermal modeling software (1, 2). In fact, Hemp concrete walls just 200mm thick produced an 80% reduction in heat variation (3) and a 95% reduction in humidity variation (4) – all while replacing traditional insulation materials that use toxic chemicals or non-sustainable components.

Due to the properties of the Cannabis fibers and the action of the lime binder, hemp concrete (or hemp lime) is naturally anti-bacterial, anti-fungal, and it repels insects & rodents.

It is practically fireproof, which means it can even be used as a fireproofing material – replacing chemical Intumescents and passive fire suppressants (5).

Hemp concrete also creates an alkaline indoor environment, as it absorbs CO2 from the indoor air (6). This means your walls, floor, and ceiling could be fighting off bacteria, mold, insects, and rodents. This is also synergistic with modern research into the benefits of alkaline environments for humans.

One final point comes down to simple chemistry. As Hemp concrete ages, it actually gets stronger. The hemp fibers will wick moisture out of any wooden beams nearby as the lime binder replaces that moisture. This not only protects any wood from rot, mold, and pests, but it also helps to harden and strengthen the wood – basically petrifying it. So buildings constructed with cannabis will actually get stronger over time and less susceptible to decomposition.

Too Good To Be True?

If Hemp concrete really does have all of these beneficial properties, why isn’t it being used? If it truly is CO2 negative, and growing it is actually good for our planet, then why aren’t more people producing Hemp concrete buildings?

Two reasons: Cultural stigma, and lack of education.

The great news is that both reasons are slowly fading, and more and more buildings are being constructed with earthling-friendly hemp concrete. But you can help out! Educate yourself about this wonderful material and really prove to yourself that it is as good as all the hype. Then tell others about it.

The only way to change public perception is to spread information, but we need to be sure and spread accurate information. Stay tuned to this website for more accurate and educational information.


  1. Hemp-Lime Performance in Danish Climatic Context. Thermal Conductivity as a Function of Moisture Content
  2. Construction green breakfast – you don’t have to be a hippy to build with hemp!
  3. Construction green breakfast – you don’t have to be a hippy to build with hemp!
  4. Construction green breakfast – you don’t have to be a hippy to build with hemp!
  5. Wikipedia – Flammability
  6. Hemp: A material with a long story.
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