A look inside the restoration of Notre Dame cathedral

Summary

In 2019, a fire severely damaged Notre Dame Cathedral, prompting firefighters to preserve the structure and priceless relics. Restoration scientists from the Laboratory for Historical Monuments then began analyzing the stone, mortar, and lead roof to guide the rebuilding process. The fire weakened the cathedral's limestone, and lead contamination posed health risks. Researchers are also studying medieval construction techniques, including the wood and stone used. Their work aims to restore the iconic structure and preserve its history for future generations.

Takeaways

• 🔥 Firefighters carefully extinguished the 2019 fire at Notre Dame, using low water pressure to protect delicate elements like stained glass.
• 🖼️ A key priority was to save priceless relics and works of art from the cathedral.
• 🧪 Restoration scientists took over after the fire to assess damage and guide the cathedral's reconstruction.
• 🏛️ Temporary wooden supports were installed to prevent the walls from collapsing after the fire destroyed the roof and part of the ceiling.
• 🧱 Notre Dame was built with limestone, which weakens at high temperatures; researchers studied the color of the stone to assess damage.
• 💧 Firefighters’ water hoses caused some limestone to absorb extra weight, altering the structural balance.
• 🌬️ Lead from the roof melted and became airborne, creating toxic conditions that required careful handling during restoration efforts.
• 🔬 Researchers are studying materials from the cathedral, like wood and stone, to uncover details about its medieval past.
• 🌲 Wood beams in the attic provided clues about climate and forest management during the 12th and 13th centuries.
• 🏗️ The Notre Dame reconstruction is a long-term project, aimed at preserving its historical significance for future generations.

Q & A

What precautions did firefighters take when fighting the Notre Dame fire?

Firefighters used lower water pressure to prevent further damage and avoided spraying stained glass, which was vulnerable to shattering.

Who took over the efforts after the firefighters controlled the Notre Dame fire?

After the firefighters, restoration scientists from the Laboratory for Historical Monuments took over to evaluate the damage and guide the restoration process.

What was the first priority for the restoration team at Notre Dame?

The first priority for the restoration team was stabilizing the cathedral, as the fire had damaged the lead roof, wooden timbers, and created holes in the vaulted stone ceiling.

How did the fire affect the balance of forces in the structure of Notre Dame?

The fire damaged the vaulted ceiling, threatening the balance between the vaults that push outward on the walls and the flying buttresses that provide inward stabilizing force. Temporary wooden supports were installed to prevent the walls from toppling.

What material was primarily used to construct Notre Dame, and how was it affected by the fire?

Notre Dame was primarily built with limestone, which can be weakened at temperatures as low as 300°C and can turn into lime at 800°C. Fire damage was evident from changes in the stone's color, with beige indicating stability and red or black suggesting structural damage.

What challenge did the water used by firefighters pose to the stone structure of Notre Dame?

The high porosity of limestone caused some stones to absorb almost a third of their weight in water, which further affected the structural balance between the vaults and walls.

What happened to Notre Dame's lead roof during the fire, and what precautions are being taken as a result?

Parts of the lead roof melted, dripping into the vaults, while other parts became airborne as yellow smoke, releasing toxic lead particles. This has required decontamination efforts and precautions to protect workers from lead exposure.

What discoveries have researchers made from the debris of Notre Dame after the fire?

Researchers have used stone samples to learn about the original quarries and wooden beams to study the climatic history of the 12th and 13th centuries. The shape of the beams also suggests that trees were intentionally farmed for constructing the cathedral.

How long did it take to complete the original construction of Notre Dame, and when was the iconic spire added?

It took 182 years to complete the construction of Notre Dame, and the iconic spire was added much later in the 19th century.

How do researchers view the fire in the larger historical context of Notre Dame?

Researchers view the fire as just another chapter in Notre Dame's long history, with the current restoration efforts aiming to preserve the cathedral for future generations while uncovering new insights into its past.