Flax: A fibre of the future for construction?

6 minutes of reading

09 February 2023

Resistant, light, efficient, ecological… Flax is used in construction on land and even on the sea! In 2022, the Netherlands inaugurated the world’s first linen bridge. A navigator used it to build the hull of his boat… Can this plant material really meet the needs of urban construction?

More than 80% of the world’s flax is grown in France (from Hauts-de-France to Normandy). In total, 75,000 hectares produce more than 160,000 tons of flax per year. This production has taken place for centuries, and has been able to partially resist relocation. As a reminder, it was Charlemagne in the 8th century who developed this French craft. Why are we talking about craftsmanship? Because this fibre with multiple virtues is used above all for the manufacture of textiles. And this happened long before the arrival of cotton.

Flax, a fibre for current needs for construction

Over time, linen has been used in other areas, particularly insulation. While it offers very good thermal and acoustic insulation, it is not only that that pushes it to the front of the construction scene today. In the midst of climate change, it is actually a combination of benefits – in terms of production, implementation and sustainability – that make linen a material of the future for the construction sector. Flax is an annually renewable resource (meaning: fast-growing), which has favourable climatic conditions in France. It requires few inputs – , i.e. products involved in the manufacturing process. Flax is a local plant, not a high nitrogen user, and does not deplete the soil and which offers qualities as natural as its growth! It is fully recyclable and harmless to health. In addition, it contributes to the reduction of greenhouse gases since, in the form of insulation, it is able to store CO2. This is a boon for the carbon impact of tomorrow’s buildings.

“Flax is used in the same way as traditional insulation materials. However, it has much greater heat storage capacity. It takes four times longer for the heat to pass through flax insulation. “

Flax is an increasingly versatile material

Flax wool for insulation is made from short fibres that are not used by the textile industry. They are cut into small pieces, then bonded together according to different processes (needling, application of a natural binder or synthetic resin). The material obtained is light and easy to transform. This is why flax today has a multitude of applications in construction. Unlike flax used for insulation, some of these applications bring advantages related to their long-term impact on other uses. It brings a great deal of added value for humans

Types of use of flax for construction:

Chipboards used as non-load-bearing walls in wood-frame constructions, furniture or ceilings. Flax used here is obtained from the flax shives, that is to say the fragments of straw recovered during the dyeing. These flax fragments can certainly be considered crop waste, but have long been used as livestock litter and fuel.

The floor covering called linoleum is particularly prized for its high resistance to penetration. Its main component is linseed oil, mixed with cork or sawdust and resin on a layer of jute. Linseed oil is oleaginous flaxseed. It is – very high in omega-3. – It is mainly used for animal and human food.

Linseed oil is used to protect wood, which is also a basis for natural paints. It is thus biodegradable, unlike synthetic paints. However, here again, oleaginous flax seeds are used is more and more by in women as food (including pregnant women), as well as vegetarians. This is due to its iron, protein, vitamin B9, antioxidant phytosterols and omega-3 content. This is a winning combo that reduces the risk of cardiovascular disease, nervous system and brain malformations in foetuses and even breast cancer.

With flax, the question today is no longer really whether it is a material that meets the construction challenges of the construction sector (energy saving, comfort of life, safety of human health, durability, recyclability, simplicity and speed of installation, low carbon impact, etc.), but if there will be enough flax for all the uses that this plant can meet. Since flax grows mainly in France, 80 to 90% of flax fibres produced in Europe is exported to China and India for textile purposes. In summary, this material has already been proven. It has many commercial uses.