Do you know what I think sometimes? That over time, we've forgotten about sustainable building materials that were used in the past. For example, cement used to make concrete is highly polluting because it requires a lot of fossil fuels. That's why I found it interesting to draw attention to materials that come directly from nature or deserve a second chance. Here are five examples:
Example 1: Clay and straw
These were used in the Middle Ages. Clay is a natural soil type deposited by rivers and wind. For construction, pure or fat clay with a high clay content is mainly used, often combined with straw for a sturdy structure. It provides cooling in summer and warmth in winter, as it regulates moisture and temperature. While not as strong as concrete, it's quickly repairable in case of damage. Additionally, clay and straw create a healthier indoor environment, as they breathe much more than houses made of concrete or brick.
Example 2: Hemp
Hemp fibers are used as insulation material, and there are hemp blocks for building partition walls or façades. Hemp is highly sustainable, even CO2-negative, as it absorbs more CO2 than it emits during production. Should we then consider cultivating hemp on a large scale in the Netherlands? With lime-hemp construction, you can even build entire houses. Check out the Dunagro Hemp Group's website for more information.
Example 3: Flax
Flax offers the most innovative and best building insulation in terms of technology, ecology, and economy. You can read more about this on the Isovlas website. It's ideal for breathable construction, meaning, like clay and straw, it regulates moisture and temperature in a healthy way.
Example 4: Green sedum roofs
These roofs offer a sustainable solution with ecological and aesthetic benefits. As a natural insulation layer, sedum promotes energy efficiency, reduces the ecological footprint, and mitigates flood risks through rainwater retention and local water infiltration. Sedum absorbs CO2, produces oxygen, improves air quality, serves as a habitat for insects and birds, enhances biodiversity, and contributes to a balanced ecosystem. Its reflective properties reduce heat absorption, leading to a cooler indoor climate and lower cooling costs.
Example 5: Recycled construction
Finally, materials deserving a second chance. In the Netherlands, we face the issue of millions of plastic bottles ending up in our environment. An article from 12 years ago shows they build houses from them in Nigeria, as well as reuse glass bottles. Another example from the Netherlands involves innovative minds using old shipping containers as building materials. Keetwonen in Amsterdam, the world's largest container village, offers students unique, sustainable housing. Reusing containers is not only affordable but also a creative way to build quickly with minimal ecological footprint.
Being sustainable also means investing locally
There are many more sustainable materials for construction, such as bamboo, wood, and concrete. However, sustainable building also entails considering possible transport costs that add to CO2 emissions. That's why it can be interesting to explore local building materials more often.
Alfred van Duren