On July 6, the Ramdanis became the first family in the world to move into a house that was constructed using a 3D printer, in the city of Nantes in France. Equipped with a living area of 1,775 square feet, the walls of the structure took less than two days to “build”, while installing the roof, doors and windows took another four months.
The four-bedroom home is able to comfortably accommodate Nordine and Nouria Ramdani, and their three children, all of whom previously lived in a block of congested council flats built in the 1960s. The couple say they are thrilled to be finally living in their own detached home with a garden.
The project is the brainchild of professor Benoit Furet from the University of Nantes, who worked in collaboration with the city council and a housing association. “We produced 62 tonnes of concrete to build the basic framework,” Furet tells us. “The isolated walls took only 33 hours to create, while the cost for the same was 20 per cent less compared to standard buildings.”
Understanding the process
To understand how the process plays out, imagine an old-school inkjet in which the printhead swishes from side to side to render ink on paper, layer by flat layer. That basic principle – of ejecting a fluid material, to follow a predetermined trajectory, which builds up one on top of the other – remains the same.
The difference is that the mineral- infused fluids contained within a 3D printer are able to solidify into concrete almost instantly. “Three-dimensional printing is an additive manufacturing technology,” says architect Mirko Daneluzzo, professor of Cross Disciplinary Design at Didi. “The trajectory in this layer-by-layer process is defined by subdividing the object into slices, so it becomes possible to define the outline of the shape being printed.”
The machine then converts the digital model fed into it and turns it into a tangible three-dimensional object. Obviously, the digital file needs to be carefully calibrated and uploaded with highly accurate dimensions. “Our biggest challenge was to combine and synchronise the polyarticulated robot with the automated guided one, which we did by designing highly specific algorithms,” says Benoit. His team is currently experimenting with using natural materials such as earth and clay in future projects.
"There are two construction strategies for building housing using a 3D printer. These include pre-fabricating building components in a factory and delivering the parts to the construction site. The second option is to build directly on-site with a machine that is able to cover the entire building area," adds Daneluzzo. It follows that in the latter case – which is how the Nantes house was built – the printer needs ample free and clean space to construct, set down and cure the various layers, using robotic arms, nozzles, pumping systems and lasers.
Apis Cor is another company that specialises in on-the-spot mobile construction. “In theory, the printer is able to build a whole building directly on site by printing its walls and partitions. The machine has a small footprint, so it’s easily transportable using a regular truck and does not require a long preparation procedure prior to the commencement of construction,” says Sergey Nefedov, head of the technology at Apis Cor.
"This technology can open up a lot of opportunities, such as reducing the time of construction, implementation of almost limitless designs and shapes, potential to use eco-friendly materials, and [achieving] machinery precision," explains Nefedov, adding: "Of course, there is a still a lot of R&D work required before we can implement all these advantages."
From a resident’s point of view, one of the biggest advantages of living in a 3D-printed house is that these structures display excellent thermal behaviour and higher vapour permeability, so that the temperature-humidity conditions are more pleasant inside.
“3D-printed houses work well when you need special insulation from the outside climate. You can design the walls with specific thermal behaviour, such as special tunnels to activate natural ventilation in an efficient way in hot countries,” says Daneluzzo. “Another benefit is that you do not need formwork to build a wall as you do in traditional construction, which saves time and money.”
A downside of a structure built using this technology is that it is then, literally, set in stone. “While the design of a 3D-printed house can be pre-customised to meet the needs of its inhabitants, the disadvantage is that is difficult to change the layout after it has been printed, so the house may not be flexible enough over the years to meet the changing requirements of its occupants,” explains UAE-based Hong Kong architect James Law, chief executive of James Law Cybertecture.
"Also, currently such houses are quite rough and lack panache, as the printing process is not yet a very refined technology. It is difficult to create smooth and perfect surfaces with 3D-printed concrete, for example. However, once the technology improves, it will be very possible to print intricate designs at a high quality and even realise more complex luxurious projects," adds Law, who says the technology would "work well in the UAE, especially for low-cost housing or temporary buildings that are needed for transient labour forces and project sites".
So can these homes affect or alter the conventional construction sector? Most of the experts we spoke to believe so. “3D-printed houses will disrupt some of the existing facets of the construction industry. First of all, buildings may potentially need less construction workers on-site, for many of them will be replaced by robotic printers. Secondly, much of the component-based construction industry will be reduced as buildings will be printed in situ, without the need for as many components to come together,” predicts Law.
However, as Nefedov notes: "Construction is one of the most conservative industries, and it takes big efforts to make a revolution. The input of one or even several companies is not enough; 3D-printing technology needs to be supported by universities and governments to then create a regulation base and new construction rules."