Did you know that the global construction industry is currently responsible for a hefty 37% of the world’s greenhouse gas emissions? That’s right, according to the 2022 report by the United Nations Environment Programme (UNEP). And here’s a surprising tidbit: traditional concrete, a beloved staple in construction, chips in with a solid 8% of those emissions. In response, there has been a growing interest in sustainable alternatives, and one contender gaining attention is hempcrete.

Lets talk about this hempcrete in this article.

What is Hempcrete?

Hempcrete, also known as hemp-lime, is a biocomposite material made from the inner woody core of the hemp plant, known as the shiv or hurd, mixed with a lime-based binder and water. Unlike traditional concrete, hempcrete does not require heat to produce. Traditional concrete is made from sand, aggregate, and cement, with cement being the major energy user in its production. The ingredients for cement—limestone, shells, chalk, shale, and clay—are heated to high temperatures to form rock, which is then ground into powder. In contrast, hempcrete can be formed to fit between the studs of a house as building blocks or bricks and can be used like stucco to protect the exterior walls of new and existing homes. Its lightweight and versatile nature provides several benefits, making it a popular choice for eco-friendly building projects.

History of Hempcrete

The use of hemp in construction dates back thousands of years, with evidence of hemp-based materials found in ancient civilizations. However, the modern iteration of hempcrete emerged in France in the late 20th century. During the 1980s, builders in France began experimenting with hemp and lime mixtures to restore old buildings, discovering its excellent insulating and preservative properties. Since then, hempcrete has gained popularity worldwide, particularly in Europe, where it is used in both new construction and renovation projects. Its resurgence is closely tied to the growing interest in sustainable and green building practices.

Advantage of Hempcrete

Carbon-Negative Footprint

One of the most compelling benefits of hempcrete is its carbon-negative footprint. The hemp plant absorbs a significant amount of CO2 during its growth cycle, more than offsetting the emissions produced during the production of hempcrete. Additionally, the lime binder continues to absorb CO2 over time as it cures. This dual carbon sequestration process positions hempcrete as a leading material in the fight against climate change, offering a sustainable building solution that actively reduces atmospheric carbon levels.

Strength and Durability

Hempcrete offers impressive strength and durability, although it is not as strong as traditional concrete in terms of compressive strength. Its flexibility makes it less prone to cracking under movement and settling, which is particularly beneficial in regions prone to earthquakes or ground shifts. While wood or steel framing has better load-bearing qualities, hempcrete, as infill between traditional framing, strengthens the walls against buckling.

Lightweight Nature

One of the standout features of hempcrete is its lightweight nature. Hempcrete blocks weigh significantly less than traditional concrete blocks, reducing the load on foundations and structural supports. This property not only simplifies construction processes but also leads to cost savings in transportation and handling. The reduced weight does not compromise the material’s robustness, making it an attractive option for a variety of construction projects.

Energy Efficiency and Insulation

Hempcrete excels in energy efficiency, thanks to its superior insulating properties. The material has a high thermal mass, which means it can absorb and store heat, then slowly release it, maintaining stable indoor temperatures. This thermal regulation reduces the need for artificial heating and cooling, leading to substantial energy savings. A research suggests that the R-value of hempcrete is to be between 2.4 and 4.8 per inch, comparable to other fibrous insulations like straw or cotton. In contrast, concrete has an R-value of 0.1 to 0.2 per inch, making it a poor insulator. Hempcrete’s breathability also allows for better moisture management, enhancing its insulating capabilities and contributing to a healthier indoor environment.

Naturally Non-Toxic Composition

In an era where building materials are scrutinized for their impact on health and the environment, hempcrete stands out as a naturally non-toxic option. Made from natural hemp fibers and a lime binder, it contains no synthetic chemicals or volatile organic compounds (VOCs) that can off-gas and compromise indoor air quality. This makes hempcrete an excellent choice for eco-conscious builders and those aiming to create healthier living spaces.

Resistance to Fire, Water, and Pests

Hempcrete is renowned for its resistance to fire, water, and pests, attributes that enhance its longevity and safety profile.

  • Fire Resistance: Hempcrete is naturally fire-resistant. The lime binder forms a barrier that protects the hemp fibers from igniting. In the event of a fire, hempcrete does not release toxic fumes, adding an extra layer of safety.
  • Water Resistance: Hempcrete is vapor-permeable and can absorb and expel moisture effectively. Research shows that hempcrete can hold more than 1,300 pounds of water vapor per cubic meter without degrading, making it ideal for use in high-humidity environments.
  • Pest Resistance: The alkaline environment created by the lime binder deters pests and rodents, which often plague other building materials like wood. This pest-resistant quality reduces maintenance needs and extends the lifespan of hempcrete structures.

Conclusion

Hempcrete is more than just an innovative building material; it represents a shift towards sustainable construction practices that prioritize environmental health, energy efficiency, and long-term resilience. Its unique properties—strength, lightweight nature, energy efficiency, superior insulation, non-toxicity, and resistance to fire, water, and pests—combined with its carbon-negative footprint, make hempcrete a game-changer in the civil engineering industry. As we look to the future, embracing materials like hempcrete will be crucial in constructing buildings that are not only durable and efficient but also environmentally responsible.

By integrating hempcrete into more construction projects, we can pave the way for a greener, more sustainable world. Civil engineers and builders alike should consider hempcrete not just as an alternative, but as a primary material for sustainable construction.

Feel free to reach out if you have any questions or need further information on incorporating hempcrete into your next project. Let’s build a sustainable future, one hempcrete block at a time.