Shall humanity return to earthen shelters?
Mario Cucinella Architects and WASP suggest establishing new, greener buildings using soil and 3D printed technology. And the first prototype of TECLA (the tech-clay habitat) is already a thing.
Equivalent to around 8% of humanity’s annual carbon emissions, cement industry is a highly polluting sector and results in large amounts of waste. The move to 3D-print concrete, that is shaking up the construction industry, threatens to exacerbate this problem, by further simplifying and speeding up the building process. Can a greener solution be envisioned for us to keep building -thus managing to host the 83 million people being added to the world’s population every year- without harming our planet?
Mud blocks, rammed earth and other soil-based solutions remain important vernacular building materials around the world and have the potential to drastically reduce carbon footprint when a cradle-to-cradle life cycle approach is considered. However, soil, especially when not stabilised, is obviously not as strong and durable as concrete and, what is more, many regulations do not include earth constructions. Therefore, it is no surprise that the hegemony of concrete, as a building and printing material, is currently not questioned at all.
Nonetheless, a fully Italian team, led by Mario Cucinella Architects and WASP, has envisioned a new paradigm of construction that uses soil and naturally sourced materials to produce buildings that are specifically adapted to the climate and context for which they are conceived. TECLA, the next tech-clay habitat, is therefore not only an innovation in the field of architecture, by challenging the cookie-cutter houses concept, but it is first of all the result of a solid research. The team, also including researchers, chemists and structural engineers, has worked side by side for over a year to convert soil to a strong and durable building material that would be environmentally friendly, thus managing to bring substance and new arguments to the debate.
If the earth mixtures used for traditional buildings were made empirically, it is today possible to evaluate compositions and optimise components. The optimised mix design, whose main components are local earth, straw, rice husk, lime and water, is designed to be easily extruded through a nozzle to build layer-by-layer structural components. The most critical properties are shown to be extrudability and buildability (with the aim of building structural components without formwork). These properties are significantly influenced by the mix proportions and, above all, by the presence of water. Therefore, the main aim of the research was to maximise the mechanical strength of the mixture while also allowing for its extrudability (i.e. maintaining a certain fluidity). By gradually integrating local soil with water and additives -whose quantities vary according to the specific components of the soil itself-, and through a series of samples produced and analysed in the laboratories of Mapei (a world leading company in the additives sector and part of the Team), the mix design has finally met all the required performance standards set by Milan Engineering.
The result of the process is a construction material that, despite its optimised performances, still has all the limitations of earth (i.e. no bending resistance). Most of the 3d-printed prototypes produced so far are limited to simple vertical walls (the perfect shape to be printed layer upon layer without much trouble). These walls are then to be coupled with an external structure bearing a traditional horizontal rooftop. One of the main objectives of the project, however, was to challenge this vision, to achieve a fully 3d-printed building, without recurring to traditional bearing structures that would end up, among other things, diminishing the expressive potential of such new technology. Besides, by reducing the presence of other materials and techniques in the building site, the constructions can be fully printed on site (with the only addition of frames), thus significantly speeding up the works and reducing the errors resulting from the juxtaposition of different elements. Hence, the building would mostly withstand compression forces and, therefore, resist by shape. While some initial conclusions were drawn from a series of empirical experiments (small-scale trial and error printings), it soon became necessary to move to more specific and reliable simulations able to consider the precise properties of the optimised material as well as seismic and accidental loads. The final shape is composed by a combination of three self-standing modules: two domes and a saddle. To conclude, it is not to be forgotten that the building had to be printed layer by layer without the use of any kind of formwork and, therefore, it is was not only the final shape that needed to be self-standing, but also all the intermediate ones.
But the challenge here was not only developing one single prototype. With the soil properties varying enormously across the globe and TECLA wishing to be exported and adapted to possibly any context, one might wonder what happens once we change spot. To allow for the actual exportability of the concept, the whole process is currently undergoing a phase of parametrisation, so that, once the location is known and soil samples are taken, the additives and water shares are automatically calculated to meet the required performance standards.
Although such deep building paradigm change is not going to happen overnight, the first seed of doubt was planted. The first prototype of TECLA, after only 200 hours of printing, stands to question the supremacy of concrete and paving the way for the oldest and eco-friendliest of building materials to make a comeback. In a world that is now faced with unprecedented challenges, is humanity ready to embrace a new (but totally ancestral) way to live in harmony with our planet?
IMAGES CAPTIONS: TECLA village: 3D-printed earthen dwellings for sustainable living (design by: MC A)
A project by Mario Cucinella Architects & WASP
- Mario Cucinella Architects: Architectural design and management
- WASP: Engineering and 3D printing construction
In collaboration with:
- Milan Ingegneria: Structural consultancy
- Mapei: Materials consultancy and supply
