The construction industry is consuming more than 40% of the total energy and resources across the globe. The construction industry must be moving towards more sustainable practices to face occurring climate changes. For this reason, the industry is stirring away from using building materials that are mined or harvested from the forests.
The industry is switching towards using renewable resources, and hemp is the perfect material that is gaining huge popularity in the construction industry, with a hemp mixture known as hempcrete.
Hempcrete is one of the bio-based building materials that can be used to restore, renovate, or build any kind of building from apartments to houses and from service to public sector buildings, and from listed historical buildings to traditional buildings.
What is Hempcrete?
Hempcrete or hemp-lime is one of the most incredible building materials made from industrial hemp. It is a bio-composite material, which can be used in the construction as an alternative to traditional building materials like concrete.
Hempcrete is made from the balsa wood-like core of the cannabis sativa plant. This material can be mixed with water and lime to form hempcrete. It has high silica content, allowing it to bind well with lime. Hempcrete is a lightweight material and only weighs approximately one-eighth as compared to concrete.
The material is widely used in construction for centuries across Europe. However, hemp is now grown widely by certified commercial growers. The strain of hemp plant contains as low as 0.3% of THC, the psychoactive substance found in cannabis. This is quite a low level when compared to those found in medicinal and hallucinogenic varieties of cannabis (contains 5-10% of THC).
Fully dried hempcrete blocks will float in water. The material is not used as a structural element but as an insulating infill between the frame members. All the load is carried by the internal framing. In Europe, as much as 10-story buildings have been constructed using hempcrete.
While hemp is grown legally in Canada and Europe, it was illegal in the United States for several decades. However, with the gradual liberalization of laws in the country, the hemp production is getting legalized.
How are Hempcrete Blocks manufactured?
Traditionally, the hempcrete blocks were prepared at the site by mixing the raw material and then placing it into the formwork, or by using the equipment. Initially, this process required highly qualified workers.
However, with advancements in technology and an increase in the demand for hempcrete, hempcrete blocks are manufactured at the industry level. The production process of these blocks are divided into three steps:
- Mixing: Hemp shives, water, and lime are mixed to create hempcrete. The raw materials are dosed proportionately and mixed.
- Molding: Hempcrete obtained from the previous step is poured into the blocks of varying widths using a special press.
- Open-air Curing: The frail blocks are placed on an automatic conveyor belt after some time, which takes the blocks to the storage area for open-air drying. Drying is done to add strength and hardness to the hempcrete blocks. Blocks require about 6-10 weeks to get ready for usage. This time duration varies with the width of the block.
Applications of Hempcrete
- As roof and floor insulation
- As plasters
- As internal and external wall insulation
- New buildings
- For insulating old buildings
- Renovations
Benefits of Hempcrete
- Naturally Sourced Material
Hempcrete is completely organic, and the manufacturing doesn’t involve any synthetic component. Moreover, it doesn’t need a huge amount of energy for production, making it a highly environment-friendly material.
On the other hand, traditional building materials such as concrete have a large carbon footprint and are a major cause of concern for the whole planet.
Hempcrete is a very low maintenance material, and it requires little to no caring. Once used in insulation, the material lasts for years and can help protect the structure of the building from various elements in an effective way.
The material is substantially dense as compared to traditional insulating materials. Thus, the use of hempcrete can help reinforce the structural capacity of the building. Moreover, the material provides an excellent surface for plaster finishes.
Hemp building material is used extensively for constructing buildings in earthquake-prone areas as the low density of the material renders it resistant to breakage under movement.
Walls made from hempcrete are highly breathable, and it allows the moisture to pass through. It also has low thermal conductivity and wind-resistant properties, which makes it an ideal insulating material.
- Handles Moisture Efficiently
Due to the porous nature of the material, hempcrete can absorb a large amount of moisture without causing damage to the building’s structural integrity. The plant fibers also have a huge amount of internal surface, which also acts as a storage for moisture. Once the conditions are favorable, the material releases the absorbed moisture content.
The hemp plant is carbon absorbent, and this property is imparted to hempcrete. For every cubic meter of hempcrete, it sequesters about 100 kilograms of carbon. When compared to the conventional construction materials, this amount is huge, as the conventional materials contribute to carbon emission during the manufacturing process.
The most important feature of hemp building material is its resilience to common problems faced by traditional building materials. It is highly resistant to flame, making the material an inherent fireproofing material.
As lime is used in the binding process, the material is also resistant to fungus and possesses antimicrobial properties. This leads to resistance from the formation of mold even in high humidity conditions. The material is also parasite-resistant.
- Excellent Insulating Properties
With its antifungal, moisture absorbent, and antimicrobial properties, the material is a great insulator during both cold and hot climates. The material is perfect to use in areas with extremely high humid climates.
Additionally, it also has outstanding soundproofing properties, making it an ideal material for blocking the external noise.
Hempcrete is an extremely lightweight material. As mentioned earlier, it weighs only one-eighth of that of concrete. Due to its lightweight, the material can be easily transported to greater heights.
- Recyclable and Non-Toxic Material
It is a non-toxic building material and doesn’t percolate any harmful substance into the building structure. Hence, the material doesn’t harm the construction and the inhabitants of the building in any way. Hempcrete is biodegradable, and it can be easily reused.
Due to the multiple benefits of hempcrete over traditional building materials, hempcrete is gaining huge popularity in the construction industry. More and more companies are coming forward to manufacture hempcrete blocks. The material can be used in a wide range of construction projects. The possibilities are endless, and so does the benefits of the material. Hence, it can be one of the best choices available for construction companies in the future.