The Institute for Advanced Architecture of Catalonia (IAAC) has completed the 3D printing of a new low-carbon building prototype using locally available soil and natural materials. IAAC employed a Crane WASP 3D printer to create the experimental lightweight building as part of an expansion of the institute’s 3D Printed Earth Forest Campus in Collserola Natural Park, Barcelona. The project represents an important step in the development of a sustainable, zero-mile, and affordable housing model.
WASP - World’s Advanced Saving Project
WASP - World’s Advanced Saving Project was established in 2012 in Massa Lombarda, Italy. Drawing inspiration from the potter wasp, a wasp that builds its own pot-shaped nest made of mud, WASP designs and produces large-scale 3D printers that seek to benefit humankind — the company’s 3D printers are used across a range of sectors, including housing, energy, health, and food. Revenue from the sale of WASP’s printers is invested in research and development, with a focus on improving prosperity for all. WASP is particularly focused on printing healthy, human-scale clay houses using the universal availability of earth.
Crane WASP 3D printer
First developed in 2018, Crane WASP is a collaborative 3D printing system that is capable of constructing buildings from locally sourced natural materials, agricultural waste, and standard building materials. Its design reinterprets the archetypal building crane from a digital manufacturing perspective. The printer can be assembled in different configurations depending on the printing area. Crane WASP can work with clay, aerial and hydraulic lime, cement, aggregate, and natural and polymer fibers.
An affordable and sustainable housing solution
An affordable housing crisis is affecting people in many areas of the world. A United Nations report highlights that “1.6 billion people around the world lack adequate housing and basic services.” It is projected this could rise to three billion people by 2030. Following more than ten years of research, IAAC and its “Postgraduate in 3D Printing Architecture” program is combining a traditional material with cutting-edge technology to “propose an affordable and sustainable housing solution.” Moreover, 3D printing that uses earth sourced on-site is an especially sustainable method of construction, contributing greatly to a circular economy.
3D Printed Earth Forest Campus
IAAC’s research into the new lightweight building prototype in Collserola Natural Park was reinforced by a recent collaboration with global architectural firm Hassell. The project was initially a prototype (funded by Hassell) for an upcoming community center project in Tanzania that involved the development of a full-size earth-printed wall. IAAC then expanded the initial prototype into a full-scale pavilion.
The first phase of IAAC’s 3D Printed Earth Forest Campus was named TOVA (completed in 2022 as part of the Postgraduate in 3D Printing Architecture) — it was the first 3D printed building in Spain to be constructed using earth and a Crane WASP. “The 3D Printed Earth Forest Campus is an architectural intervention with a number of enclosed, covered, and open spaces made from 3D printed earth that also serves as a live laboratory for the testing of new constructive and architectural solutions,” explains IAAC. The project aims to create a number of rooms from a range of perspectives, demonstrating how buildings can adapt to the needs of their users.
The 3D Printed Earth Forest Campus is constructed in the main from natural materials. A fifty-centimeter natural stone foundation provides stability and drainage. Above ground, the first thirty centimeters of each wall consists of a solid stabilized earth base, protecting the building from flooding and rain. The base was cast-in-place using an earth-printed formwork — this was later reused as material for printing the walls. The wall thickness varies from forty to seventy centimeters, depending on the weight of the load to be carried and the degree of protection from solar radiation that is required.
The earth walls are made using material that is sourced just a few meters from the site: the earth is excavated below 0.5 meters to avoid organic content; dried in the sun, it is then sieved to remove any large stones; the earth is mixed with water, an organic fiber and natural enzyme; the mixture is then pressed into the 3D printer. The wall is printed daily at a rate of 25 centimeters in height, thereby avoiding collapse owing to its weight — it reaches a height of 2.5 meters (eight feet) in approximately ten days. The timber roof is installed when the walls are partially dry; the roof both rests on and is anchored to the earth walls.
The use of 3D printing allows for a high level of customization in design. “Depending on their position within the project, the walls combine different performances,” says IAAC. “They are structural, holding their own weight and the weight of their roofs (potentially used in multi-story buildings); they act as thermal barriers and humidity regulators; they frame small openings for light and views as well as controlling natural ventilation.” Printed walls are 50 percent hollow and their cavities can be used for insulation and the integration of services.
TEIXIT
TEIXIT, the next phase of the 3D Printed Earth Forest Campus, extends the campus with the creation of a lightweight building.
TEIXIT sits adjacent to TOVA, extending the living and working area of the campus. The lightweight building’s construction addresses the question of “how much daylight can travel through a structural earth wall?” Earth walls are typically both thick and opaque — 3D printing technology offers flexibility in design, meaning an earth wall can be constructed with a high level of porosity that allows a controlled amount of light through its depth. By depositing one layer at a time, a network of 20-centimeter-wide openings is created.
TEIXIT is a 50-square-meter (538-square-feet) open space consisting of three earth-printed walls — printed over a period of four weeks — that support a wooden roof. Post-tensioning cables, inserted through the inner cavities of the walls, anchor the roof to the foundations, balancing wind uplift forces. The overhanging roof helps to protect the unfired earth walls from water damage; an organic oil water-repellent treatment is also applied.
The addition of TEIXIT to IAAC’s 3D Printed Earth Forest Campus takes the institute’s research one step closer to developing a carbon neutral architecture that is adapted to the needs of its users and the environment.
