Why We Should Be Building with Dirt

Did you know earth, the ground we walk on and grow our crops in, is the most abundantly used building material on the planet? With over 3 billion people living, working, learning, playing, and socializing in buildings constructed from materials such as soil, clay, mud, and cob. Earth material technology has also been studied, improved upon, and refined for thousands of years. However, building with earth is often associated with being poor, backward, and primitive. All over the world, industrialization has led to an abandonment of earth building traditions, replaced by heavy investments into expensive and fossil fuel dependent materials such as steel and concrete. Earth, on the other hand, is a material with excellent thermal mass properties and low embodied energy. In West Africa, building with clay or adobe can be traced back thousands of years. The Dogon people of what is today Mali and northwestern Burkina Faso had developed a highly sophisticated earth building technique that is now at risk of disappearing due to the ongoing military conflicts. In Vitruvius's Ten Books on Architecture, a seminal architectural treatise from classical antiquity, there is an entire chapter dedicated to mud brick masonry. Vitruvius saw it as a material that exemplifies what he believed to be the primary qualities of architecture, fermitus, utilitas, and venustus. The Egyptian architect Hassan Fathi, known for improving the techniques of traditional mud construction in Egypt, utilized the thermodynamic properties of earth to create passively cooled structures on a large urban scale. His highly influential book, Architecture for the Poor, demonstrated how mud brick is a low-cost, sustainable, and beautiful material available to essentially everyone on earth. The reason earth building materials are excellent thermal masses is because they act as natural thermal batteries that absorb heat during the day and slowly release heat at night, which can maintain comfortable interior temperatures without the need for mechanical heating and cooling during all seasons. Earth assemblies generally have a high R-value, which means it's a very insulating material that can lead to lower energy consumption even when mechanical heating and cooling are used. Earth also requires very little energy to extract and manufacture and is made of highly recyclable content. At the end of an earth constructed building's life, they simply melt back into the ground, which can be reused to grow vegetation or harnessed in the future for building materials again. So why has the industrial world largely rejected earth construction? It may be due to the fact that soil composition differs from region to region, making it difficult to standardize on a large industrial scale. It is in fact illegal to build with mud brick in some regions due to building code regulations. Are these decisions made entirely for safety reasons or were they results of lobbying by industrial material manufacturers not wanting their businesses to be threatened by such a low cost, abundantly available, and versatile material? While mud bricks are not permitted by certain building codes, the use of compressed earth blocks, CEBs, is often welcomed. CEB was first invented by French architect Francois Cointreau in 1803 when he developed a mechanical press to compact earth into dense blocks. In 1952, Colombian engineer Raul Ramirez made a critical advancement to CEB technology by inventing a manually operated machine that is small, portable, and capable of mass production. A critical ingredient of CEB is mixing a small percentage of cement to stabilize it, resulting in higher material strength and weather resistance. CEB also requires very little moisture to produce, does not require firing or curing, can be used straight out of the machine, does not shrink or crack, has a smooth surface which can be left exposed without a finishing overcoat, and is considered aesthetically pleasing due to its natural appearance, appealing to humans' affinity to biophilic materials. An innovative example of CEB construction is by the architect Diabeto Francis Carey, who employs the use of locally available resources, traditional material techniques in consort with modern solutions, and local community participation in the design and building process. Carey is from Gando, a small remote village in Burkina Faso, which is a landlocked, low-income West African nation with limited natural resources. The nation has also been experiencing frequent extreme climate events and tremendous political instability in recent years. There is little to no access to education in Gando. In 1985, Carey received a scholarship to study carpentry in Germany, and in 1995, he decided to enroll into the architecture program at Berlin's Technische Universität. While he was studying at TU, villagers back in Gando asked him for help with repairing the village's only school, built after he left, which was at risk of collapse. In 1998, he established a charity, School Building Blocks for Gando, to raise money for building a new school, and began working closely with the community on the design. The new primary school building, completed in 2001, is comprised of three detached rectangular classrooms under a single inclined roof. The walls are built from compressed earth blocks connected by earth mortar. Giving people a good education is very important to Francis Carey. So before I tell you more about his school design, I want to tell you a bit about today's highly educational sponsor. 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Industrial materials like concrete and steel are hard to come by in Gando, and wood is minimally available due to deforestation. Thus clay is a material widely used for buildings in the region for the past several hundred years. However, it's often considered a temporary material as it tends to wash away under heavy rains. Carey believed in the use of clay because it's free and locally available. The reddish earth color fits organically into the surroundings, and it has a historical connection with the people. To improve performance, the clay compound was mixed with about six percent cement to achieve stable and uniform bricks that are more weather resistant. He also introduced the portable manually operated press, making it possible to easily produce CEBs on site. To address the sweltering hot conditions where temperatures can often get as hot as 45 degrees celsius, Carey pulled the building's roof away from the top of the classroom. This results in a stack effect that creates a continuous air circulation by drawing in cool air from the windows, which rises through the perforated clay ceilings and vents out the perimeter gap below the roof canopy. This design feature alleviates the need for costly and energy-intensive air conditioning. Thus, a passively cooled building with a low ecological footprint was created out of necessity. Francis Carey's designs are able to achieve durability, usefulness, and beauty through paying close attention to the simplest building block of architecture, the material. He also demonstrates why a deep connection to material culture may be the key to achieving economic independence for developing African nations, as well as creating a more sustainable future for the rest of the world. So is earth, this building material of the past, actually the material of the future? Maybe. I personally think we should be building with mud and clay a lot more than we currently do, but it obviously isn't a solution in every scenario. I think the more important lesson we should take away from earth construction is a careful consideration of limited resources, passive building techniques, human factors, and local cultures. Let me know what you guys think in the comments below. As always, thank you guys so much for watching. I recently decided to go back to school for a master's degree, and this video is actually an adaptation of one of my assignments. If you enjoyed this video, feel free to check out more like it right here, and I'll see you guys next time. Are these decisions made entirely for safety reasons? I don't know. I have no idea as to that.