Prefabrication experiments - 198 - current practices - 09 - Additive manufacturing and low-cost housing

The premise of prefab has always been to achieve affordable, customizable, quickly built, sustainable and efficient housing systems for the many. If the adaptable building kit was last century’s response to the pursuit, this century’s solutions seem more akin to what would have been identified as science fiction only a few decades ago. The use of robots in building, partly in reaction to the greater use of information technology from planning to fabrication and construction, is reforming prefab concepts, particularly when it comes to on-site 3d printing of components and systems.

3d printing or additive manufacturing consists of continuously depositing layers of material from a computerized moving nozzle. Reinforced clay, cement-based polymers, polyurethane foam and fibre-reinforced concrete are just a sample of materials being explored to generate mass construction systems. Primarily suited to compressive shapes, vertical walls, arched vaults, domes or shells, the accumulated strata authentically translate the construction process.  The nozzle’s three-axis displacement is precisely controlled and determined from a computer model comparably to any 3d slicing software used in comparable small-scale 3d printing. Speed, material temperatures, viscosity, thickness and web structure are optimized to enhance overall cementing, strength and material savings. 

Certainly not the first and only 3d printed home experiment on the market, the Batiprint3d project established at the University of Nantes has caught attention for its use of polyurethane expandable foam as a customizable formwork into which reinforced concrete is poured. The system is relatively inexpensive and avoids costly and specifically rectilinear formwork, which is usually discarded. The 3d printed formwork is deposited in any shape and once cured with the concrete infill creates a strong bond and a superior insulated wall. Particularly suited to contexts where material procurement and delivery are difficult, however this simple construction method can be deployed in any context. The robot is mounted on an automated vehicle and controlled with laser precision making any shape where verticality or compression is maintained as the principle acting force. As robots make their way into the construction industry, the 3d printed house will surface from the research laboratory as demand for quality, low-cost and quick dwellings increases at an exponential rate. 

Batiprint 3d is a collaboration beteween Laboratoire des Sciences du Numérique in Nantes (University of Nantes, CNRS, Ecole Centrale, Inria, IMT Atlantique) and the Institute of Civil and Mechanical Engineering Research, CNRS, Ecole Centrale)