An experimental 3D printed building made of local soil

The Institute for Advanced Architecture of Catalonia (IAAC) completed the 3D printing of a 100 m2 low carbon emissions building prototype using local soil and natural materials.

Called the 3D-Printed Earth Forest Campus, the project functions as a sort of live laboratory for the testing of new constructive and architectural solutions. It is constructed for the most part of natural materials. The floor plan is fragmented and deconstructed to show the potential flexibility in architectural design provided by the digital technology of 3D printing.

A foundation of 50 cm of natural stone guarantees stability and drainage. The first 30 cm of the wall consists of a solid 40-70 cm thick, stabilised earth base to protect rom floods and rain. This base is casted into an earth printed formwork, which was later reutilised into the printing of the walls. The earth walls are made from material sourced a few meters away, excavated from below 0.5 m to avoid organic content. The material was then dried in the sun, sieved to filter larger stones out. It was mixed with water, organic fibre and natural enzymes, until finally pressed into the Crane WASP 3D printer.

The walls were printed at a rate of 25 cm height per day to avoid collapse under its own weight. They have three different functions: a structural one, as a thermal barrier, and as a humidity regulator. They have small openings for light, but also for controlled natural ventilation and integration of insulation and services. The walls are left 50 per cent hollow, saving material use. The walls of this project seek a certain lightness and light porosity made possible by the construction technique, depositing layer one at a time, creating small local cantilevers into a network of 20 cm wide openings.

When partially dried, the roofs are installed, which rest on and are anchored to the 2.5 m high walls. In some cases, the connection to the timber roof was post-tensioned with steel cables down to the foundations.

The project is a collaboration between IAAC, WASP (large scale 3D printing), SOCOTEC (structural consultant), Hassell (global architecture studio), Vervictech (enzymes provider), and Colette (a philanthropic organisation).

Photos: Iwan Baan (finished project) / IAAC/3dPA (construction phase)