You may have heard of hempcrete and hempwood in recent years but hemp has been used as a building material for thousands of years.
Back in the 6th century when France was known as Gaul, a bridge was constructed using a hemp mortar
But since the 6th century building methods have changed, it seems we are reverting to using more traditional materials in more innovative ways.
Hemp is one of those products making a comeback, not only for its strength, mould and heat resistance making it perfect for a building material, but for its environmental impact too.
But can hemp really be the answer?
It may not be the overall solution but it can definitely go some way to making a positive impact.
We need to find a more sustainable cleaner, environmentally friendly option
Trees for many years have been used as building materials but this material is becoming less sustainable as the population and demand grows.
Trees take anywhere from 50-100 years to grow to full maturity so it can be a lengthy process to grow and produce a finished product that can be used within the industry. Whereas Hemp can be grown in as little as 100 days. The overall yield will be much higher from hemp just due to the speed it can be grown, making it a more sustainable product in the way of growth.
Adding an adhesive to the hurd from hemp can actually make a product 15% stronger than Oak as Tasmanian Company Smart oak has found.
They have created an ‘Engineered Wood’ by bonding stands, fibres and particles with adhesives.
After the 2014 Farm Bill removes Hemp from Schedule 1 Controlled substances, they created a hemp version of their wooden product.
This wood is denser than oak and more sustainable due to the growth time.
So we know there are wooden alternatives out there, but there’s more than just wooden materials used in construction, that need to be replaced.
There are already alternatives for loose wool, Thermowelded panels, acoustic dampening felts and many more products with compositions containing as much as 85% hemp based material. Bringing down usages of lesser sustainable materials throughout the industry.
But this isnt enough… Construction consumes over 30% of the global energy, 20% of the global water, and 35% of global resources.
So we need to do more.
Swapping concrete for a plant based / hemp alternative could be another way forward?
There are already a number of companies out there using a Hemp-crete type product.
Hempcrete is a Hemp-lime mortar where hemp hurds are mixed with lime based binders and water.
The unusually high silica content in the hurds allow it to bind with the lime in a similar way to the bonds in Portland cement.
When hempcrete is created it has a density equal to approximately 15% that of concrete so cannot be load bearing, but may be used in connection with load bearing frames such as wooden studs.
Hempcrete is a great insulator of heat and noise due to the pockets of air in the material, and is relatively breathable making it a great alternative.
The material is also resistant to mould, and fire-resistant. “We heat [our material] up to over 1,500 degrees Fahrenheit and it barely has an impact,” says builder Mark Faber, of Canadian hempcrete company Just BioFiber.
The benefits are so clear that if you build a house with Hempcrete in England, you can even receive an insurance discount.