Hemp houses: the cost, the benefits, the future
This little house looks pretty regular, right? What if we’d tell you it’s actually made from hemp?
The concept of a hemp house is not so contemporary as it might appear. In fact, it was used in ancient times.
The most famous site is probably a hemp mortar bridge in France from the 6th century. It’s still standing. Also, the famous Colosseum in Rome had sunscreen awnings made from cotton, flax, and hemp.
The building sector uses a material known as hempcrete. It’s a mix of hemp hurd (the woody essence of the hemp plant), hydraulic lime, and water.
There’s also an option to use hemp blocks, which are basically prefabricated building blocks. These are less common, mainly because the use of hempcrete is more studied.
As cool as this all might sound, hempcrete can’t be used to construct the entire house. This is because it isn’t suitable for load-bearing walls, and the foundation structure has to be made out of timber and steel.
Nevertheless, everything else can be made out of this biomaterial.
The material of hemp has the ability to absorb and lock in carbon dioxide, thus reducing our negative impact on the atmosphere.
In comparison, cement production alone is responsible for 5% of the entire carbon emission on the planet. Plus the energy consumed for the heavy machinery used by the building sector.
Also, the majority of the hemp house making labor is done by human hands and wooden tools that don’t use electricity.
Have you ever heard of “Sick building syndrome“?
It’s basically when you feel weird, nonspecific symptoms (could include headache, dizziness, nausea, eye, nose or throat irritation, dry cough, dry or itching skin, difficulty in concentration, fatigue) because of the house you live or work in.
That is because in recent decades, the indoor concentrations of some pollutants have increased (due to energy-efficient building construction and use of synthetic building materials)
In contrast, hemp houses are often described as breathable structures that provide:
A fact that can prove the durability of hempcrete: the 6th century hemp mortar bridge in France we’ve already mentioned has withstood Viking conquests, multiple world wars, and natural disasters. During World War II, the Germans tried to destroy it twice.
And it’s still there!
Hempcrete tends to harden as it sets down, meaning that time only makes it stronger. And the beautiful part of its life cycle is that at its end, hempcrete only goes back to nature, leaving no harmful waste behind – it’s completely zero waste.
To build a 1250 square foot house, it would take 2.5 acres of hemp.
However, the main obstacle is that it is approximately 20-30% pricier than concrete.
The fact that most of the work needs to be done by hands will also probably add additional cost.
The first hemp house to be built in the United States was in Asheville, North Carolina, in 2010. The overall cost was approximately $452,200.
On the other hand, a hemp house could also be seen as a investment: depending on the features of the house, it could lower electricity, heating, and maintenance costs.
A house built from hempcrete could save as much as $14,000-$25,000 in energy bills over 50 years. These savings are likely to increase further as energy costs continue to rise.
When reading about hemp houses, we’ve stumbled across Hempitecture – a platform of hemp architecture, construction and education.
Hempitecture was recently on the Forbes annual “30 Under 30” Class of 2020 for “creating the products, methods, and materials of tomorrow.” They were also the architects behind America’s first public use hemp building in Ketchum, Idaho.
“It’s now possible to build structures that are carbon negative, fireproof, soundproof, toxin free, earthquake, mold and pest resistant.” – says the team of Harmless Home.
Located in East Sooke on southern Vancouver Island, near Victoria, BC, they built a eco house using Canadian made construction technology and materials of hemp. That resulted in this revolutionary building being one answer to climate change and also providing hemp farmers with new opportunities.
Except the roof, the whole house construction is made out of hemp
Article based on:
“How to Build a House Using Hemp”, by Natalie Saunders
“Hemp Houses: A More Sustainable Way to Build and a Healthier Way to Live”, by Ana Vasi