structures dating as far back as ancient Egypt¹. However, with the current rate of the development worldwide, its production has become highly unsustainable. Especially when considering that country demanding the most concrete, China, has tripled the consumption of concrete just within the last 14 years². The carbon footprint hidden in concrete production is the main reason why it is time to look for better alternatives. The key ingredient of concrete, cement, emits the same amount of CO2 as the amount of cement produced. This means that if 10 kg of cement is produced, between 9-11 kg of CO2 is released³.
Fortunately, sustainability is becoming an important concern in the building sector, and many professionals have set their focus to address global demand for more environmentally friendly construction materials. With more people willing to pay higher price for green buildings, new companies are beginning to specialize in this field and contributing to the newest research. Some of the materials that have more recently come to the limelight have truly great characteristics and can significantly lower environmental impact compared to concrete.
Let’s have a look at 5 natural and yet effective building materials currently available:
In tropical countries where bamboo is present in large quantities, it has been used as a traditional building material for many centuries. Lately bamboo has become a popular option even in other parts of the world as a substitute to wooden framing or decking. Some of its positive properties are its resistance, durability, light weight and especially important – its renewability. Although often being used as an alternative to wood, bamboo belongs to the same family as grasses, which are fast growing, and therefore, promptly ready for harvesting. The most suitable poles for construction require only two to five years to grow before they can be used⁴!
Another great advantage of bamboo is its great fire resistance thanks to the high concentration of silicic acid and its suitability for earthquake prone areas because of its elasticity. An earthquake in the 1990s in a town of the Paeces Indians in Colombia had proven this fact, when out of the whole town only the bamboo buildings remained intact.
Using straw in construction is a sustainable replacement for concrete as it is a 100% natural material that is recyclable, renewable and non-toxic for our health. Straw is usually piled up to form walls. When built properly, straw walls perform well even in humid climates, they are less susceptible to termite infestation than wooden walls and have good insulating properties. As a byproduct of grain production, straw surplus is often burned in many countries. Transforming it into a modern building material might be the right way to utilize resources which we have readily available.
#3 Rammed Earth
Surprisingly concrete walls can be easily imitated by tightly compressed soil mixed with water and different elements such as gravel, straw or twigs. Slight alterations of this method have been used in numerous countries all over the world since the beginning of civilization. 2000 year-old parts of the Great Wall of China were built this way and they are still standing today⁵. The major advantage is that these materials are readily available and can be sourced locally, which decreases the carbon footprint of transportation. Other benefits arise from the greater thickness of the walls that create stability, provide the feeling of warmth and cosines, and serve as a good thermal buffer similar to a basement. Throughout the seasons, rammed earth walls maintain temperature indoors close to a comfortable level, which helps to save energy on heating and cooling. Rammed earth houses have proven to be able to withstand wildfires in the fire prone areas extremely well as the portion of flammable materials in the soil is minimal⁶.
It may sound rather strange but the root of mushrooms, called mycelium, has become the newest innovative material in construction. The process of obtaining building material from mushrooms is fairly simple and doesn’t emit any CO2, nor does it produce any waste. Mycelium bricks are formed when mushrooms grow around natural materials such as common farm waste in the underground without any light source. After developing an extensive root system, the bricks are baked to kill the mushrooms and then they are ready to use. The properties of this material are amazing. Mycelium is actually stronger than concrete, offers perfect insulation and comes with the bonus of being compostable⁷.
In the logging industry, bark is often considered to be just a useless byproduct. But in reality, it can be utilized as an effective roofing and siding material. Kiln-dried bark performs very well in protecting houses for up to 100 years and doesn’t need any special chemical treatment or paint. The longevity comes from its original function in nature, protection of trees from external influences⁸.
Even if these materials are not the exact answer or the most cost-effective solution for large scale projects in the long-term, they are a good starting point for tackling the growing problem of unsustainable use of concrete in construction. Let’s hope that in the near future, the variety of environmentally friendly materials will increase in popularity and it will become one of the main functional elements of newly developed buildings.