18-10-2021 Natural stone

Natural stone and Notre-Dame de Paris: 4 conferences on an unusual restoration

On December 1, 2021, as part of Heritage Day, Rocalia invites you to participate in these atypical and exceptional works.


In winter 2021, after colossal works which took two years to shore up the building, the restoration of Notre-Dame de Paris cathedral can now begin. A major task for the natural stone sector on the know-how of which the repairs will basically depend. On December 1, 2021, as part of Heritage Day, Rocalia invites you to participate in these atypical and exceptional works. Between natural stone and heritage, attend four conferences in the Rocalia forum!


Notre-Dame de Paris being secured

Check the Rocalia full program

Conference 1: "Original and replacement stones in the Notre Dame cathedral repair project"

9:30 to 10:10 a.m. — Lise LEROUX, LRMH, and David DESSANDIER, BRGM

The repairs following the Notre-Dame de Paris fire will need a large amount of natural stone. In addition to making a full inventory of the types of rock used to build the cathedral, replacement stones compatible with the original stones had to be found. Between evaluating the quarries able to provide the varieties needed, analyzing the rocks selected and then making the final choice taking into account a wide range of parameters like the difficulties of supply, the challenges were many and varied.

Get ready to enter the universe of the natural stones of the cathedral and to understand specific challenges like the looks and physical-mechanical compatibility between the original stones and “new” replacement stones – as well as discovering the methodologies and the techniques used to study the stones used for monuments and in the building stone quarries!

Conference 2: "3D digitalization in the archiving, documentation, and restoration of heritage sites via the Notre Dame cathedral case study" 

10:20 to 11:00 a.m. — Gaël HAMON, Art Graphique & Patrimoine

Gaël HAMON is a stonecutter who has become a specialist in photogrammetry and lasergrammetry, a “radiologist of our cultural heritage”. His conference will address the vast Notre-Dame cathedral 3D digitalization project which began before the fire, primarily focused on the roof truss and frame. A digital databank enabled a comparison of the structure before and after the disaster – greatly helping the architectural diagnosis.

Explaining AGP methodology – already in use for 30 years – and its application in the case of Notre-Dame de Paris, the conference will provide key elements on the many uses of new technologies, not just to exceptional works but also to smaller heritage conservation and valorization projects. So make way to BIM and 3D scanning!

Read also: BIM, a revolution in natural stone use

Conference 3: "The doctors treating Notre Dame de Paris"

11:10 to 11:50 a.m. — Régis DELTOUR, MOLLARD DELTOUR

The Pierrenoëlle company and Régis DELTOUR worked together on shoring up Notre-Dame de Paris cathedral. He studied and executed the masonry reinforcement systems for the installation of the wooden support frames under the buttresses of the nave and choir and then the vaults that made it possible to erect scaffolding inside Notre-Dame.

A dangerous job requiring particularly thorough precautions to protect workers from the high level of lead in the atmosphere and on surfaces. This conference explains the context of the works carried out by Régis DELTOUR’s teams to shore up the building so the audience can understand the highly specific and unique environment of this “once in a lifetime” mission!

Conference 4: "The Future for Heritage Professions"

12:00 to 12:45 p.m. — Discussions with the Compagnons du Devoir (trade guild) and feedback on SIPPA 2021

This conference will be an opportunity to revisit the Compagnons du Devoir (Stone Mason’s Guild) International Symposium of Heritage Professionals in Arles held from September 29 to October 3, 2021. This year, the theme of the event was “The future of heritage-related trades” and the problems shared by many natural stone professionals.

There will be three speakers:

  • François Goven, honorary Historic Buildings general inspector and editor-in-chief of the Review “Monumental”.
  • Bruno Combernoux, Director of the higher stone trades research and training institute.
  • Noëllie Duperret, traveling carpenter, member of the “Study and reproduction of the Notre-Dame de Paris trusses” team project

So make sure you note in your diary to attend these exceptional conferences on December 1 at Rocalia, the natural stone trade fair!

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This day is organized in partnership with the CAUE Rhône Métropole, the SIPPA and Untec.

© Photo credit: UlyssePixel / Adobe Stock

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