Rebuilding Notre-Dame cathedral (Paris)

I did not know this until the fire, but the cathedral is owned by the government of France, not the Catholic church. I would guess most non French people don’t know that either.

I guess a legacy of the French Revolution?

During the height of the revolution, it was used as a stable. Among the things being discarded, like the calendar and the imperial measurements, was the religion that had supported the old system and the right of kings. It’s amazing how much people will agree to when the alternative is having their head cut off. It was eventually returned to duty as a church, but I don’t think the government was in a hurry to give the church back a lot of real estate.

That would require that no one observes it. A neat trick that even David Copperfield couldn’t pull off with stooges, select camera angles, and so on.

Just 2 weeks after the fire over $800 mil was donated to rebuild it. Which might be more than is needed

https://www.bbc.com/news/world-europe-48039770

While there were certainly some concepts related to secularization within the French revolution carried on, the transfer of Catholic Church ownership to the state was more than a century later. All Catholic churches, not just Notre-Dame, then existing became property of the state because of a law passed in 1905.

To take a step back, my sister is an architecture professor living and teaching in France. She had already been teaching as a professor in the US based on being a licensed architect* before going back to earn her Masters and PhD in Paris. One of the things she did to earn extra money as a grad student and since was leading high end tours at Versailles and Notre-Dame. The kind of tours where people pay a premium for a tour guide with her background. As a result she was a source provided to the media around the time of the fire. You probably read a lot of unattributed background information she provided around the time of the fire.

She is still involved in tours, just fewer now that there is less to see. She is still regularly engaging with some of the people involved in restoration planning. While she is not an engineer or builder, as a licensed architect she has more experience with making sure things can actually be built than those that merely have PhDs. She was home for Christmas. Guess what got discussed? Some bits captured from some of those discussions:

  • None of the professionals thought that Macron’s five year goal was feasible.
  • There are trained construction workers that build using ancient techniques in France. There are many centuries old buildings that require the use of those old skills for repair and maintenance. They need to train more for a job this big. There is already interest in those jobs. One of the concerns is managing how many new traditional skill artisans they train. If you train enough to rebuild quickly what do they do when the jobs dry up?
  • The walls were in serious risk of falling in the immediate aftermath of the fire. A strong wind would have been enough to potentially knock them down. Fortunately, the weather held until after they got bracing in place.
  • There are options that would still look and function reasonably accurately even if they are not original. She brought up other metal roof options for the old lead roof. If they choose less lead, but not lead free, lead coated copper roofing is one option, for example.
  • The stories about the concerns that prompted the sudden spate of rebuilding being 50-50 miss an important nuance. It is not that they couldn’t rebuild if things get worse. They could. They rebuilt some, but not all, old structures that were effectively leveled during WWII. The stories we are seeing now are more conveying that if it gets worse they probably won’t rebuild. It’s already a ludicrously expensive and difficult job. If the expenses and difficulty skyrocket further that may well kill the project.
  • A couple years before the fire, there was a Professor that came in and laser mapped the structure. There are some bits with poor coverage in his data but dominantly they have the structure accurately mapped to very small measurements. I want to say it was within millimeters. Sadly that guy died so he won’t get to see any results.
  • I know that sounds odd but it is a thing in architecture. It takes a lot of time, effort, and real world experience to actually become a licensed architect. Many of the instructors with PhDs in her former department here in the US were not licensed. Any designs they may have produced couldn’t legally be built without someone like my sister approving.

If it’s too expensive to rebuild it I think they will build a smaller version from scratch, possibly on the same site.

The story specifically says pledged not donated. It is an important distinction. From last summer

French billionaires slow-walk donations to rebuild Notre Dame

Most of that pledged money has yet to be actually donated.

Snopes debunks this: “The central flaw in the argument is that an average of all the cells in a body masks the fact that some cells last very long times, and other cells don’t regenerate for a person’s entire lifetime…”

France has its own Forest of Troncais, built hundreds of years ago to provide long oak for ships (and ironically finally coming of age in the mid-1800s.)

So it’s possible that the cathedral needs even longer oak than that. And even so some people say that in order to truly recreate the old technique you need to cure the oak in oil for years, but I don’t know anything about that.

Except that story has since moved on. As it was always obvious that it would.

Indeed. While they do have a vested interest in wanting a full-scale timber reconstruction, French foresters have ridiculed the media reports suggesting that there wouldn’t be enough oak.

Nor does such optimism seem unwarranted. It is worth remembering that Viollet-le-Duc was able to source oak to replace about a third of the roof structure in the mid-nineteenth century. Yet that was at a time when French forests were at their all-time smallest extent. One of the paradoxes of industrialisation is that it often reverses deforestation, in part because less wood gets used for fuel. Such has been the case in France, where forests have actually almost doubled in size over the past two centuries. That’s helped take the pressure off older woodlands, which are now better protected anyway.

Seasoning the oak may be more of a problem. But that’s just an issue of the time scale, not of whether a reconstruction would be possible.

Since the original took some 200 years to build, I’d say they had the time to season any oak that’s cut today.

I’d wonder how the massive lead contamination factors into this, too. They would have to thoroughly clean and re-clean everything of all that dust.

Wood soaked in oil? What could possibly go wrong?

The question is whether they want to rebuild exactly as it was, use traditional materials only for the visible surfaces, or simply give the appearance of the old building?

I imagine the professional traditional builders are used when the goal is to restore a portion of a building - ie. rebuild the staircase, or re-plaster a deteriorating room - and the goal is to maintain the current

For example, the same spire with the same look could be built on a frame of stainless steel and be far less susceptible to future fires or rot or other damage. Similarly, the roof can be any type of beams, maybe steel, does not need to be solid oak; and the covering under the shingles, also modern materials - rather than over-engineered oak planning (I assume) it could be sheets of steel or something.

These are all decisions to be made in the next few months (years, at this rate?). How important is it to rebuild exactly as it was way back when? Is it work the extra hundreds of millions of Euros?

Perhaps a similar scale of project - almost - was the Venice Opera House La Fenice, destroyed by fire a few decades ago…

(Wikipedia, as usual) So they only tried to make it look as much like the original as possible.

The roof of Chartres Cathedral burned in the 1830s and it was replaced with an iron frame and copper shingles. https://en.wikipedia.org/wiki/File:Chartres_roof_space_the_Charpente_de_Fer.jpg By now that’s an historical construct in its own right, but I don’t see why a similar solution for Notre Dame made of modern steel would be out of the question. This is especially considering the fragile nature of the remaining walls and buttresses. A properly engineered truss roof can relieve a lot, if not all, of the outward stresses on the walls by tying them together and resolving those forces within the roof. That wasn’t possible in medieval times when construction took centuries to complete, and before they knew how to engineer beams, columns, trusses, etc. beyond just piling more mass against it and hoping things would work.

Ok, that addition to the joke had me in stitches. :smiley:

I feel like the best idea is to dismantle anything that can’t be (safely) saved, rebuild it with modern materials and construction techniques such that it resembles the original structure and use the original parts that were taken down as a facade and/or interior decoration. Sure, right now, it might seem like it’s not the same but in 200 years the fire/dismantling/rebuilding will just be part of it’s story. Historians will talk about how the process was done, tour guides and documentaries will point out what’s original, what was done after the fire, which materials are original etc.

It’s, what, 700 years old? In another few hundred years the pre-fire/post-fire thing will only serve to make it that much more interesting, regardless of how the reconstruction is handled.

If the https://en.wikipedia.org/wiki/Dresden_Frauenkirche can be rebuilt, anything is possible.

During the 1982/1984 renovation of San Francisco’s cable car system, it was discovered the car barn and power house had more issues than anticipated.

Essentially, a new steel structure was built within the walls of the old one. They didn’t even have to take the old walls down.

That flaw is removed by the addition of the phrase “on average”.

Just like I can gather up 100 people and hand one person $100. “Every person got $1” is wrong but “Every person, on average, got $1” is correct.