Inauguration of Viliaprint: 3D printing passes its entrance exam in the construction of social housing

Plurial Novilia inaugurates on June 2 the first 5 houses entirely made of a mix of 3D concrete printing and off-site prefabricated elements. A fully reproducible model that will be shared within Action Logement for wider deployment throughout France.

• After 4 years of experimentation, the Viliaprint project mixing concrete 3D printing and off-site prefabricated elements comes out of the ground;
• The 5 rental houses (T3 to T5) that have been built in the heart of the Réma'Vert eco-district have made it possible to validate the relevance of the approach taken by Plurial Novilia and its partners in the operational phase;
• Certified ATEx by the CSTB, the process opens up new prospects for the construction of social housing, even if certain technical points still need to be refined to further enhance the effectiveness of the approach.

As explained by Alain Nicole, Managing Director of Plurial Novilia, “after 4 years of hard work, it is a real satisfaction for us to see the Viliaprint project finally materialize. All the objectives that we had set ourselves both in terms of construction technique and economic model are on the way to being achieved: 3D printing has proven itself in the operational phase and opens up encouraging prospects for our sector, in terms of performance. as deadlines for completion.

Viliaprint has indeed made it possible to demonstrate the relevance of the global approach of Plurial Novilia and its partners, both in terms of architectural flexibility (integration of curves, parabolas, ellipses, etc.) and performance (watertightness, resistance to shocks , energy performance, etc.), so many construction times since, in the long term, the industrialization of the process will greatly reduce the duration of projects. In addition, the assembly of prefabricated walls in the factory greatly reduces the hardship for the teams and the nuisance for the residents.

For Jérôme Florentin, Project Management Director at Plurial Novilia: “Our greatest pride within the framework of Viliaprint is that this innovation has made it possible to demonstrate that 3D printing is perfectly compatible with our vision of high quality, atypical, comfortable and efficient social housing. This process obviously requires a certain acculturation of the actors in the design phase as well as in the implementation phase. It is necessary to train companies, adapt sectors and strengthen short circuits. But the performances plead in favor of this technology: if the political will follows and if the donors take up the process, 3D printing has a bright future ahead of it”.

In parallel with the construction of the 5 houses on Réma'Vert, Plurial Novilia has also developed a complete technical file which can be made available to all the social landlords gathered within Action Logement who, in turn, would like develop similar operations.

The process having also been ATEx-certified by the CSTB, all the obstacles now seem to have been lifted for the massive adoption of this construction process by social housing players.

A collective project with multiple ambitions

Through Viliaprint, Plurial Novilia wanted to start from scratch and imagine what it would be possible to do in terms of social housing thanks to the 3D printing technology imagined by XtreeE. All the sliders were then pushed to the maximum, in design as well as in construction, with a view to reproducibility and sharing of experience with other donors.

The digital design tool offering great architectural freedom, original work was carried out with the firm Coste Architectures around the design of the houses.

At the same time, an objective of reducing the volume of ink (specific concrete) supplied by Vicat by 40 to 70% has been set, thanks to the optimization of cladding and structures, by producing more hollows than solids.

In the construction phase, carried out by the companies Demathieu Bard Construction, Le Bâtiment Associé and Soprema as well as their subcontractors, several objectives have been set – and achieved – in particular the reduction of construction times.

In addition, the deployment of the solution has reduced the hardship for the teams and the nuisance for the residents.

Finally, numerous pieces of equipment have been integrated into the building in order to further enhance its performance and quality of use at all levels, such as the Atlantic heat pumps.

The dimensions of Viliaprint

• A project with a social dimension, aiming to put 3D printing at the service of the functionality of housing, the comfort of its occupants and the development of territories.
• A project with an economic dimension, having made it possible to certify a new construction technique with the desire to make it reproducible, through a sustainable economic model.
• A sustainable project, which has made it possible to enhance the advantages of 3D printing during the construction phase, both on an environmental level (savings of materials, dry sector, etc.) and on a societal level (reduction of hardship for the teams , reduction of nuisance for local residents, etc.).

The main stages of the project

May 2018: Viliaprint, multiple winner of calls for innovative projects

Viliaprint was selected in May 2018 by Caisse des Dépôts and USH as part of the "Architecture de la Transformation 2018" call for projects. Open to all social landlords, this initiative aims to bring out new architectural, technical and organizational responses in the service of social and intermediate housing - replicable responses that will be shared with all social landlords. Chosen from more than 40 projects, Viliaprint first benefited from initial support from Hack'Archi, an open innovation workshop, mobilizing around them 70 students from various backgrounds, then spent 9 months in the design phase. incubation in order to test the solutions and validate the methods of their generalization within the LabCDC, the incubator of innovative projects of the Caisse des Dépôts group. The project also won the heart of the jury of ALINOV, Action Logement's innovation fund.

April 2019: printing of the first wall prototypes

In order to test the reliability of the concept “in situ”, Plurial Novilia and XtreeE printed several prototypes of 3D concrete walls. Significant work was carried out on the concrete, supplied and specially developed by the cement group Vicat – a high-performance mortar directly transformed in the printing head of the XtreeE robot. The various prototypes made it possible to refine the mixture in order to reinforce the waterproofness or the shock resistance of the walls - but also to validate the essential of the initial intuitions.

November 2020: obtaining ATEx certification

Legislation not allowing the use of 3D printed elements as integrated elements in the load-bearing structure of a construction, Plurial Novilia and XtreeE asked the CSTB (Centre Scientifique et Technique du Bâtiment) to validate the technical principle imagined through the ATEx certification. The favorable opinion, given after numerous exchanges and technical adjustments, also made it possible to validate the insurability of the real estate project and, by direct effect, the possibility of renting the printed houses.

June 2021: connection of the walls and assembly of the houses

After 3 years of testing and preparation, Viliaprint returned to the operational phase in the summer of 2021 with the first bonding of printed concrete walls - and therefore the assembly of the first houses. On the plot, everything was ready to accommodate the printed walls: the foundations had been made, as had the paving and the structure of posts and beams. All that remained was the installation and bonding to be done. In addition to the site manager, a team leader and two experienced formwork masons supervised this operation, which required cranes to the millimetre. The on-site erection of the walls took just over half a day for a one-storey house.