The newly installed nacelle avoids the 426 steps by climbing along the imposing stone piles to the gutters of the building, nearly 60 meters high, from where the view plunges between the gargoyles towards the houses. half-timbered.

Seen up close, the lead plates making up the roof are warped over time: despite the multiple patches, they are no longer watertight and will be recast to better protect the framework.

With its 2,000 m3 of wood entirely assembled by hand, part of which dates back to the 13th century, the forest of Saint-Pierre de Beauvais cathedral “is an exceptional testimony to the heritage of carpenters”, says Henri Martin, chief architect. historical monuments.

In the attic, the wood vibrates to the sound of the bells and creaks everywhere when the wind blows. But the harmonious assembly of oak beams, some felled in 1257 as evidenced by the dating, has kept all its symmetry.

Medieval craftsmen left traces of their work there: assembly marks, and an ingenious lifting device to hoist the materials needed to build the vaults.

– “Smothering a start of fire” –

The renovation aims to reinforce the parts damaged by grafted elements, without replacing entire beams.

The major project includes the installation of an innovative fire-fighting system, to prevent a tragedy similar to the fire that ravaged Notre-Dame de Paris in 2019, when the lead roof of the Paris cathedral was under renovation.

In the event of an alert, thin pipes terminated by nozzles whose holes are the size of a pinhead will project water under pressure to create a mist. Already used in cruise ships or high-rise buildings, the technique is being studied for Notre-Dame.

It is a question of creating “a humid tropical atmosphere making it possible to suffocate a start of fire”, without waiting for the firefighters, or pouring out harmful quantities of water, explains Mr. Martin.

“Before, we tried to save the public, now we are trying to save the building as well, which is much more complicated,” says the architect.

The works amounting to 17 million euros, partly financed by the State via the recovery plan, should be completed at the end of 2026.

– “Babel Tower” –

“It is a building that has had some misfortunes, but it is one of the most beautiful Gothic buildings in France”, underlines the prefect of Hauts-de-France, George-François Leclerc, who came to inspect the site on Wednesday.

The restoration will also make it possible to remove the imposing wooden props put in place 30 years ago due to the structural fragility of the monument.

Because the ambition of the builders to raise a building whose vault culminates at more than 48 meters in height, the equivalent of 17 floors, was not without excess.

For Hilaire Mullon, regional director of cultural affairs, this architectural epic evokes “the Tower of Babel”.

Twelve years after the completion of the choir, in 1284, a tornado weakened the flying buttresses, and part of its stone vault collapsed.

Work did not resume until the 16th century, with a tower culminating at 157 meters, which made the cathedral the highest monument in the world. Until on Ascension Day 1573, four years after construction was completed, the tower collapsed under its weight.

If the frame resists, the cathedral will therefore remain unfinished, without a nave.

But its vault, which braved the bombardments of the center of Beauvais at the start of the Second World War, remains among the highest in the world. It surpasses by a few meters that of Saint-Pierre in Rome, and by 15 meters that of Notre-Dame in Paris.