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nieuws  08-11-2023 

Beneficial hemp

8 november 2023 werd bekend dat de ministeries van BZK, I&W, LNV en EZK €200 miljoen investeren in het bevorderen van biobased bouwmaterialen om de milieu-impact van de landbouw, industrie en bouw te verminderen. Lees hier de publicatie van Volkshuisvesting Nederland.


Een goed moment om dit recente artikel uit NOOK Symbiose over Hennep online te zetten.







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Historically, hemp has something of a bad rep, which is a shame because it’s an incredibly sustainable building material. And one that can reduce greenhouse gas emissions in all stages, from construction to maintenance. Nook spoke with advocates of hemp – a farmer, a producer, and an architect – about the many benefits of building with this material.


Carbon footprint negative

Michel Post, architect and founder of ORIO Architects, is a self-described energetic architect. He believes a building can be more than merely a ‘roof over one’s head’. The immediate surroundings are vital to the experience and energy of a space, building, or environment. “Everything is energy,” says Post. “If we want to establish a renewed connection with nature, it begins with how we perceive our built environment and its influence on us.” Through his architectural firm, Post has designed various ecological, organic, and sustainable buildings using natural materials such as wood, flax, straw, lime, clay, and hemp. “Hemp is a remarkable building material. It is one of the fastest-growing crops, and purifies the air by converting large amounts of CO2 during its growth. It can reach heights of almost four metres in three to four months, and grows in almost any type of soil. Because of its rapid growth, there is no need for weed control, eliminating the need for pesticides.” As a building material, hemp also has a positive carbon dioxide content. In fact, when combined with lime, known as hemp- crete, it can even make a building’s carbon footprint negative. “By using hemp fibre, water, and lime, a mixture is created that provides not only good insulation but alsopossesses excellent acoustic properties,” Post explains. “The material can buffer temperature and humidity, prevent mould growth, and create a comfortable, healthy environment within a building. It is fire- and pest-resistant, lightweight, and forms a hard, vapor-permeable wall, preventing excessive humidity and condensation.”


Can fibre hemp get you ‘high’? The answer is a resounding NO.
Thijs Adrichem


Reviving an ancient crop

Hemp is also a versatile building material. It can be poured in place using a slip form, sprayed onto an existing structure, stacked as hempcrete blocks, or pur- chased as prefabricated panels for direct installation. And it’s great for insulating buildings, which HempFlax has facilitated since 1993. The company was started with the goal of restoring the ancient crop of fibre hemp to its former glory. Today they successfully cultivate fibre hemp in the Netherlands, Romania, and Germany. “At our production facility in Germany, we produce bio-based insulation. It consists of 66% fibre hemp, 22% recycled jute, 8% PET binder melt fibres, and 4% soda for fire retardancy. It is not a new product, as it has been manufactured since the 1990s and is a certified natural insulation prod- uct,” says Thijs Adrichem of HempFlax. The advantages? It can be easily custom- ised with commercially available tools, is very easy to install, provides long-lasting heat retention, and is safe for humans and animals – it is non-irritating to the skin, and no protective measures are required during installation. Apart from the ma- terial’s health benefits and thermal and acoustic properties, another significant advantage is that, as fibre hemp grows, up to 15,000 kg of CO2 per hectare is stored and retained in the crop. Adrichem: “With our insulation, you can truly make a differ- ence compared to the use of environmen- tally harmful traditional insulations.”


1. Hemp benefits
It is a remarkable building materi-
al. It is one of the fastest-growing
crops, and purifies the air by con-

verting large amounts of CO during 2

its growth.


2. Hemp benefits
As a building material, hemp com-
bined with lime, known as hempcrete,
can even make a building’s carbon
footprint negative.


In the midst of the CO2 farming crisis, hemp emerged as a promising solution with the potential to revolutionise sustainable agriculture and environmentally friendly construction.


Room for growth

Sounds almost too good to be true. But there are also some disadvantages to working with hemp. For example, while hemp insulation has many applications in construction, it cannot be used as flat roof insulation or in damp areas. Another downside is the fact that the market for traditional insulations remains large and powerful. According to Adrichem, “Biobased insulations do not have the economies of scale that traditional insulations possess, and despite growing demand, the market remains relatively small and not comparable to traditional alternatives, price-wise.” The good news is that the gap is closing, because traditional insulations require a significant amount of energy iput compared to what it takes to produce hemp insulation. Arguably one of the biggest challenges when working with hemp is the fact that it is a still relatively unknown material. “Not only is the knowledge of bio-based materials relatively limited among clients and the construction industry, but current regulations also require bio-based materials to comply with the same standards as traditional materials. This creates an uneven playing field, like comparing a Dacia car to a Mercedes, and hinders the equal promotion and development of bio-based materials,” Adrichem argues. Educating people and raising awareness about the benefits of hemp also involves downplaying any perceived negative side effects. “We still receive daily inquiries about whether fibre hemp can get you ‘high,’ and the answer is a resounding no,” says Adrichem. “Fibre hemp has a rich and functional history and is distinct from female Cannabis indica, which is used for its high THC content (i.e., marijuana).” Although industrial hemp fibres do not contain psychoactive substances, they are often subjected to the same legal restrictions as marijuana. “Due to the association with marijuana and the lack of knowledge about fibre hemp as a versatile raw materi- al, a stigma developed around its use. This contributed to a negative perception of fibre hemp and hindered its utilisation.” From the 1990s onwards, there was a resurgence in interest and cultivation, and fibre hemp began to be widely used in various applications. Today, its applications are diverse. But there’s room to grow. Adrichem explains how “hemp insulation has been used as a building material in Germany, Switzerland, Austria, France, and Belgium for a long time. In contrast, the Netherlands has traditionally relied on steel, concrete, bricks, and mineral insula- tion. However, there is a positive trend in new projects with a greater focus on using bio-based insulation such as hemp, as it provides a significant advantage in reduc- ing the carbon footprint of a building due to its CO2 storage capacity. Additionally, many people have chosen hemp insulation despite the higher price, recognising its benefits in the previously niche bio-based market. Despite the challenges of scaling up production and increasing awareness among the industry and consumers, hemp undeniably has the potential to play a crucial role in a sustainable future.”


Hemp is a versatile construction
material: it can be poured using
slip forms, sprayed onto existing
structures, stacked as hempcrete
blocks, or installed using
prefabricated panels.


3. Hemp benefits
Traditional insulations require a
significant amount of energy input
compared to the production of hemp


4. Hemp benefits
Due to its rapid growth, there is no
need for weed control, eliminating
the use of pesticides.


Low-maintenance crop

Over the years, Wim Vos of the Dun Agro Hemp Group has seen a steady increase in both interest in and demand for fibre hemp. A farmer himself, Vos helps other farmers manage the entire fibre hemp process, from seed to harvest. “It’s a very low-maintenance crop,” Vos explains. “Once you’ve planted the hemp, you don’t really have to do much until it’s time to harvest, so farmers can focus their attention on their other crops. Hemp is also a fast-growing crop, doesn’t need watering or any pesticide treatment, and has deep roots, which improve the overall structure and quality of the soil.” With all the benefits attributed to hemp, it’s a wonder not more farmers are turning to this crop, especially in light of the Dutch government’s plan to halve emissions by cutting livestock numbers and production. That same government, though, compli- cates matters with red tape and regulations. “The current policy isn’t helping,” Vos claims. “The numbers simply aren’t adding up. There is no financial incentive. In fact, the way things are set up right now, a farmer can yield up to ten times more from an acre of protein crops instead of fibre crops like hemp.” Still, he believes that the future for hemp fibre is looking bright. “It’s a beautiful product. It’s a crop that actually cleans the ground, and with all the building restrictions and rising costs of materials, we’re expecting an even bigger demand in fibre hemp.” [Anneloes van Gaalen]


This article was published in our magazine #2 2023: NOOK Symbiose – building in harmony with nature. You can order NOOK here






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