Rebuilding updates: January & February 2021
Since the new year, work on Notre-Dame de Paris is steadily progressing as we continue securing the structure of Notre-Dame Cathedral. We anticipate this work will be finished in summer 2021. Now that the scaffolding has been removed, the cathedral will be placed under a temporary umbrella-like structure above the crossing of the transept, nave, and choir to protect its interior from water damage. Installing this protective structure was finished in February.
The vaults connecting the crossing of the transept were also covered with platforms which allowed rope access technicians to safely anchor themselves so they could clear debris from the vaults. This removal process took place in three stages:
- Removing most of the remains of wood and metal. These remains were deposited, sorted, and are now stored in warehouses in Paris. This was completed in January 2021.
- Clearing and bagging ash and dust to be sorted by archaeologists. This work is still ongoing.
- Removing lead dust via very high efficiency suction to reduce the levels of lead dust remaining in the cathedral and to make the environment safer for upcoming projects. This work is still ongoing.
Work is also planned to repair the rib vaults adjacent to the crossing of the transept. This work will be carried out by stonemasons and consists of applying plaster in the gaps and the exposed ends of the stones. For more fragile pieces of the vaults, plaster will be reinforced with fiberglass.
The last major step in the Safety Phase will begin in the next few weeks with the installation of wooden scaffolding that will support the most fragile vaults of the cathedral’s interior. This scaffolding will also allow for half-hangers – a construction support structure – to be inserted under each rib of the arch and then stabilized on the scaffolding.
Commonly used in the safeguarding of historical monuments, this method of shoring up a structure is often scaled to fit. The five sexpartite vaults in the choir, the north transept and the nave will be outfitted with made to measure half-hangers that fit the shape of each vault and account for the complexities of the building. This work is expected to be completed this summer.
The Role Science Plays in the Reconstruction
The rebuilding and restoration work for Notre-Dame de Paris has presented a unique opportunity to use modern scientific advancements to learn more about the cathedral and streamline the rebuilding process. In December 2020, an operation was launched to test a protocol that, during the restoration, would allow the reinforcement of the supporting walls without replacing the existing stones. After the project management team and Historical Monuments Research Laboratory defined a procedure for the first zone, the tests began in February.
Science also plays a role in reassembling the collapsed arch in Notre-Dame Cathedral’s nave. Starting from scratch, scientists researched and created a 3D model of the keystones and stone blocks in the double arches which then allows restorers to estimate the number of stone blocks that can be reused for reconstructing the vaults.
What’s Next for Notre-Dame Cathedral?
After the Safety Phase is complete, works on Notre-Dame Cathedral will move into the Restoration Phase. In preparation, diagnostic studies are underway to establish the program of work and a schedule in order to estimate the total cost of the entire operation and respect the French government’s goal of reopening the cathedral in April 2024.
These studies, carried out by Notre-Dame Cathedral’s project management were delivered in two stages. The first was sent to the French public agency in charge of the restoration in mid-December 2020 and the second part was sent in mid-February 2021.
The public agency examined the first set of studies in conjunction with the project management team. These studies will also be reviewed by the Ministry of Culture in charge of scientific and technical monitoring, along with two Inspector Generals of Monuments and the Regional Archaeological Service. Once the stakeholders involved approve these studies, the Restoration Phase can proceed and plans for the rebuilding of the cathedral will be finalized.