Hempcrete Housing: An Overview
Hempcrete is taking the construction industry to new heights. With more and more countries creating laws and legislation that allow for hemp cultivation, the historic plant has resurfaced as a sustainable and viable means to construct houses and buildings to combat the ill effects of global warming.
Quite possibly its greatest gift is what it takes away. Hempcrete is carbon-negative; it can absorb and store hundreds of kgs of carbon and remove it from the air. Taking into account the litany of other benefits it provides (more on those below), it is no wonder that more people are looking to build their homes using this green and eco-friendly material.
Hempcrete is made from hemp hurds (also known as shives), which are a fibrous woody core found within the stalk of the plant. These hurds make up about 70% of he plants biomass and it is simply mixed with lime binder and water to create a mixture that is strong enough to build houses (note that hempcrete is not load-bearing).
Hemp Houses Are Quake-Resistant
A low-density material, hempcrete is resistant to cracks on movement. Walls built using hempcrete are 7 times stronger and 3 times more elastic than walls which are constructed using traditional concrete.This strength of hempcrete makes it an effective earthquake-resistant material which can be used to build houses in earthquake-prone areas.
Hempcrete Houses Are Fire, Heat And Water Resistant
Beyond saving us from cockroaches, hempcrete also has the capability to protect us from heat and fire. Hempcrete is fireproof as well water-resistant (it can recover from water penetration without molding). It also resists excessive heat and keeps your house at an optimum and controlled temperature due to the material’s breathability. When considering all of these benefits and their impact on multiple weather conditions and situations, it’s clear why there is a growing demand of consumers who want a home that is not only stylish but is safe.
Hemp Houses Are Environmentally Friendly
Just like other plants, hemp absorbs carbon dioxide from the atmosphere. Meaning, carbon gets locked away the hempcrete walls, blocks and insulation during the construction process. Theoretically, 165 kg of carbon can be absorbed and locked up by 1 m3 of hempcrete wall during manufacturing. This alone is enough to state the benefits of hempcrete buildings for our environment. But if you needed more reasons to believe, hempcrete is 100% recyclable and reusable and can be used as fertilizer once destroyed.
A Hempcrete Success Story
Former Asheville mayor Russ Martin and his wife Karon Korp built the first US hemp house in 2010 using hemp crop which they imported from The UK.
“Hemp is a great option and a sustainable product that should be more widely accepted and used,” says Karon Korp, who together with her husband, lived for six years in their hemp house in North Carolina. They worked with designer Anthony Brenner to create the home’s features and brought the idea of building their house using hemp.
The house was 3,000 square feet and the couple lived there for six years. They found the insulation factor of hemp quite effective even when the house was at a higher elevation. Moreover, the cost of their home’s average monthly energy bill was $100, which at the time was below average than the homes of similar size. Karon also said that they were less prone to allergies while living there for six years.
The house was sold for $685,000 in May 2017 and was one of its kind. Source.
Hemp House FAQs
If you are planning on building a home constructed with hempcrete (or building it yourself), we have some FAQs for you before starting.
1. How much hempcrete is used to build a house?
The quantity needed mainly depends on the area of the house that is being built. On average, it takes around 2.5 acres of hemp to produce enough hemp hurd to build a house of 1,250 square feet.
2. How much does it cost to build a hempcrete house?
The fixed price for hempcrete materials is approximately $135 per square meter based on a 300 mm thick wall. Source.
3. What sort of house designs can be built using hempcrete?
Hempcrete can be used to construct almost any type of house such as:
- Passive house
- Dog house
- Tiny house
- Tiny duplex
- Tiny Row House
4. Is Hempcrete better than concrete?
It is easier to work with hempcrete than the traditional lime mixes. It lacks the brittleness property of concrete, so it doesn’t require expansion joints. Concrete also emits carbon and limits ground absorption of precipitation. The result is a raised ambient temperature that reduces the growth of land and cuts off life in the underlying soil.
To learn more, view our post that compares hempcrete to other building materials.