Two topics are also particularly important at the French natural stone trade fair Rocalia this year (December 05 – 07, 2023, Lyon): on the one hand, the reuse of stone and thus its role in the circular economy, and on the other hand, building with solid stone, i.e., the use of stone as a load-bearing material, as was customary for thousands of years and had survived in modern form in a market niche in France after World War II.
In Dry Stone Walls as a Habitat for Animals and Plants, both themes are brought together. The examples shown go back to projects in recent years in France that have become known under titles such as “Walls for Biodiversity“.
The “Pavillon de Versailles,“ a flat hall with stone outer walls, has become famous. It was created in 2022 by dry stone wall specialists Joël Jannet and Martin Muriot, with architectural advice from Chartier Dalix: natural stone waste from road construction (limestone, porphyry, sandstone, and gneiss) was used, the individual pieces of which were selected in such a way that they did not have to be cut up further and no new waste was created.
The walls made of the irregular pieces are filled with earth, so that in the cracks and exposed stones openings green curtains figuratively pour down. “This building is a demonstrator of the hidden resources of the city: it reveals the potential of dumped materials, the value of their re-use and encourages reflections on the restoration of ecological media in urban areas,“ comments François de Mazières, Mayor of Versailles.
For the Jane and Paulette Nardal Park in Paris, leftover pieces from the city’s road construction were brought together, lying around somewhere in district warehouses as paving slabs, pavers, curbs, or other materials. With their help, a green-blue arrangement was created, to be understood as a habitat for animals and plants, including water zones. The landscape architects of Atelier Nous created four thematic zones as play areas for the children and as mini-amphitheaters for the grown-ups with numerous street furniture, in which the stones experienced a new use.
An installation with references to these two projects will be on display at Rocalia.
The second theme is about solid construction with natural stone. Models are shown of how walls can be assembled from ashlars. Different options of how the stones interlock were tested and evaluated by PhD students of the GSA Laboratory (ENSA Paris Malaquais). Such construction methods can greatly reduce the construction time and also allow the disassembly and reuse of the entire masonry substance at the end of the building’s life.
Giuseppe Fallacara, professor of architecture at the Politecnico di Bari, had shown innovative projects at previous editions of Rocalia, in which prestressed stone elements were used to create spectacular structures for trade fair stands or shells in concert parks.
Now he is showing the prototype of a project in which he has turned to 3D printing stone powder. It’s a shelter wall where people can shelter from rain or wind. The name “Origami“ gives a hint of the concept: a flexibly interlocking framework made of iron is filled with slices of aluminum honeycomb and thin stone and can be bent in many directions or extended indefinitely.
Rocalia is the only exhibition of the stone sector in France. There the stone manufacturers of the country present themselves with numerous varieties, which sell very well with the image “Made in France“ and the reference to the culture of the country. Manufacturers of machinery or tools are also prominently represented.
On the history of Rocalia: after more than 10 years without such an sector meeting in France with the end of the show called World Rock Expo in Montpellier, it was relaunched in 2017 under the initiative of the trade magazine Pierre Actual, this time in Lyon, where Pierre Actual is located. The partnership with the exhibition of landscaping, Paisalia, placed at the same time in the exhibition halls next door, has proved to be a success.
(10.11.2023, USA: 11.10.2023)