Building with Dirt

filed under: 
Image credit: 
Rajesh Thakkar

What we call dirt, mud, soil or even earth is a wonderful ecosystem of microbial and insect life that sustains all plant life and is a fundamental part of the larger natural ecosystem of the planet. It is a crucial participant in the various cycles of nature such as the water and carbon cycles, plants and dirt too have a symbiotic relationship where one cannot exist without the other. Without the plants, the dirt would be washed away to sea leaving behind barren wastelands where hardly anything would grow.
Man too has had a unique relationship with dirt, sometimes using it for its therapeutic value and for millennia, as a building material. By living in a structure of dirt, we had a direct connection with earth, as the dwelling was a seamless part of the whole, in harmony with its surroundings.

Why build with dirt?
Before the advent of modern construction materials, man used various naturally available materials such as dirt, rocks, straw, dung, lime, etc for building small and large structures. Numerous structures built with natural materials have stood the test of time and survived beautifully for hundreds if not thousands of years. The typical considerations while building a structure would be cost, longevity, structural strength, impact on the environment, maintainability, weather handling, etc. When we look at dirt in the context of all these considerations it has been proven that not only is it significantly cost effective but also remarkably energy efficient, keeping the interior comfortable at all times of the year. Even today we see houses in rural areas that are more than 35 years old and still in great condition, thus their structural strength and longevity are well established. Given these facts, it makes immense sense to build with dirt and other locally available natural and recycled materials.

But going beyond these typical considerations, there could be a deeper reason and meaning as to why we should live in dwellings made of dirt. An interesting characteristic of dirt is that it is breathable; in such a dwelling, the walls no longer separate the outside from the inside but are an integral part of both the outside and the inside. The dwelling is not built on the land as an imposition or in an attempt to separate or divide but in continuance of the surrounding connecting us to all that is around us. Unlike the modern materials such as brick and steel – which are very rigid, hard and stiff – dirt by its very nature is flexible and malleable allowing for any shapes, regular or otherwise. This allows us to create designs that reflect not only the local sensibilities and culture but also the relationship of the dwelling with the surroundings. It also provides immense (and exciting) scope to use waste materials such as old vehicle tires and discarded plastic bottles to make parts of the structure such as windows and skylights.
What is dirt made of?
When we think of using dirt as a construction material, we need to understand its properties and behavior. Besides microbial life forms and organic matter such as roots, leaves, etc, dirt is mostly made of sand, silt and clay with the size of the particles decreasing in that order. The clay part, with its smallest particle size, is what gives dirt the ability to bind and hold together. Typically, dirt with 30% clay content is ideal for building activities as it holds together very well without crumbling or cracking. How to build with dirt?
There are various well-established techniques for building with dirt, with the most common ones being cob style and rammed earth. In cob style, the dirt is first dampened and mixed thoroughly by stamping on it, and then mud lumps are placed in layers to build the walls. Other materials such as straw and husk are often added to the dirt to give it additional adhesiveness.
Though these techniques have existed for thousands of years, the various rammed earth techniques for building with dirt are getting increasingly popular. As the name ‘rammed earth’ suggests, the technique involves packing the dampened dirt into a form by tamping it using a manual tamping tool. One of the popular methods under this technique is ‘Earthbag Construction’.
Building a Dream
For a very long time I have wanted to build structures with dirt that were sustainable yet practical in every respect. The first such experiment began 7 years ago when I built my house using compressed mud blocks, local stone, filler roofs, dirt plaster and dirt paint. But somehow that wasn’t enough because the structure still used some quantity (although significantly less) of high energy materials such as cement and steel. It was with tremendous excitement that I started working more than a year ago on building 5 cottages (shown in the pictures) on my farm entirely with dirt. The first things we needed on a new farm were water and a place to stay, so a pond was excavated for harvesting rainwater, and the excavated dirt was used for building the cottages. This approach is similar to the cycles in nature, where the waste from one meets the needs of another.
Building a mud house is more than just construction - it is the expression of a wish to align harmoniously with Nature and adopt ‘systems thinking’ as a way of life, where one sees all parts as inter-connected, leading to minimal waste and significantly reduced costs.