Imagine a world in which 3D printers, rather than the deliberate rhythm of hammers and trowels, are used to precisely construct buildings that rise from the ground. The Institute for Advanced Architecture of Catalonia (IAAC) is one of the names furthering this reality.

In response to the global predictions alarming of an acute housing crisis unravelling amidst surging climate change, IAAC has put forth a sustainable and versatile emergency affordable housing solution. Their 3D-Printed Earth Forest Campus project—a sustainable dwelling prototype that could be constructed anywhere in the world—aims to reshape architectural expression by seamlessly blending tradition and innovation. Since its construction is fast, easy and adaptable, it also supports the livelihood of local labour and can be built through locally sourced materials.

IAAC has recently completed a 100-square-metre building prototype, 3D-printed using local earth. An extension of their 3D-Printed Earth Forest Campus, the project— located in the forest of Valldaura in the National Park of Collserola in Barcelona—employed the pioneering digital technology of Crane WASP 3D printer. The built form, experimental in aesthetics and adaptable in nature, reveals a multitude of rooms, perspectives, corners, and indoor, semi-indoor and outdoor environments. The design team describes the project as ‘a labyrinth that distances itself from repetitive standardised contemporary architectural solutions’ demonstrative of a ‘high level of adaptation of buildings to their users’ needs’.

IAAC’s journey began with the first phase of the project called TOVA, a sustainable and compact 3D printed house made in collaboration with global architecture practice Hassell. Constructed with the aid of WASP Crane printers, TOVA used locally sourced earth and prioritised speedy building - an effort underscoring the versatility of 3D printing in responding to a range of housing problems. Despite its lightweight construction, the project demonstrates exceptional strength and durability, capable of withstanding harsh climate conditions. TOVA was described as "a cutting-edge 3D printing technology to print sustainable buildings made of earth" by EU President Ursula von der Leyen after receiving the "Shaping a circular industrial ecosystem" prize at the New European Bauhaus in 2023. The living and working area of the forest robotic campus in the Collserola Natural Park (Barcelona) is expanded by the recent development of TEIXIT, which is next to TOVA.

A peek into the construction of the prototype reveals a standardised, adaptable process. Describing the structural framework, IAAC explains, “A 50 cm natural stone foundation beneath the surface ensures drainage and stability. To guard against floods and rain, the top 30 cm wall is made up of a sturdy, stabilised soil base that is 40-70 cm thick. The foundation is then cast into earth-printed formwork that is then used to print the walls. The material used to construct the walls is excavated from a distance of 0.5m; to prevent the organic content.”

The formation of the earth's walls, as per IAAC, is through the subsequent drying of the earth in the sun. The process is followed by sieving to remove larger stones and then combining them with water, organic fibre and natural enzymes before it is finally pushed into the 3D printer. “The wall is printed at a rate of 25 cm height per day, to avoid collapse due to self-weight and can reach its total 2.5m in approximately 10 days,” IAAC adds. The roofs are erected when they are partially dried; to prevent lifting from the wind; they both rest and are anchored to the earth's walls.

The building’s design takes into consideration the Mediterranean climate. Its compact size, while protecting against winter chills, can be expanded to take advantage of the surrounding outdoor space during the other seasons of the year. The network of cavities that make up the walls allows for excellent insulation against heat loss in the winter and protection from solar radiation in the summer. These cavities also allow for airflow.

Ecologically, this project, as stated, has nearly zero emissions because of its shell and the use of only locally sourced materials, which reduce waste and make it a model for low-carbon building considering that current construction practices account for 36 per cent of CO2 emissions. The project's disjointed and fragmented floor plan serves as an example of the potential architectural design flexibility made possible by digital technologies like 3D printing.

The IAAC’s 3D-printed Earth Forest Campus in Barcelona is a testament to the transformative power of architectural innovation and sustainable design. This pioneering project boldly redefines the boundaries of construction, demonstrating that buildings can be harmoniously integrated into their natural environments. By utilising advanced 3D printing technology, the campus materialises as a living, breathing entity, where architecture and ecology coexist in perfect synergy. More than just a building; it's a blueprint for the future, inspiring a new generation of architects and engineers to embrace sustainable practices and create spaces that nurture both people and the planet.

(Text by Navya Khurania, intern at STIR)