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Comment by wazoox | Hacker News Reader

The question is moot. France signed the Venice Convention in the 70s, that forbids any significant modification of protected monuments. Therefore the roof must be reconstructed absolutely identically from a visual point of view, using techniques as similar as possible as the previous one.

Rebuilding in metal or concrete like Reims, Nantes etc. couldn't be done nowadays.

Building a timber structure like the one that burned being out of the question (because we lack the necessary stock of century-old oak wood that have been dipped into brine for 20 years before construction, as was the original), but most probably laminated wood will be use in its stead.

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From what I can tell, nothing in the Venice Charter says the reconstruction must be identical. On the contrary:

Article 12. Replacements of missing parts must integrate harmoniously with the whole, but at the same time must be distinguishable from the original so that restoration does not falsify the artistic or historic evidence.

https://en.wikipedia.org/wiki/Venice_Charter

The standard interpretation of this is something like the following:

If you replace an element (e.g. a brick) with a new brick, you should aim for it to blend in discreetly and convincingly with the existing structure BUT you should not try to conceal the fact that it is a repair (by distressing it, for example).

I think it would suffice to place a block somewhere in the reconstruction engraved with the date of the fire and the fact that the fire collapsed a portion of the structure, which was then rebuilt with modern techniques and materials appropriate for preserving the building as a public monument.

The danger is that more ephemeral records of the fire are eventually lost, and then a future archaeologist uses evidence from the structure to make conclusions about construction materials and methods of a particular era.

Besides that, the flying buttresses were not an original feature of the cathedral. If those could be added later, and become part of the historic character of the building, why not steel structural beams and reinforced concrete supports now?

> Besides that, the flying buttresses were not an original feature of the cathedral.

Do you have a source for that? I thought a gothic cathedral without flying buttresses was like a skyskraper without a steel skeleton. The load-bearing structure isn't generally added to a building after the fact.

https://www.nytimes.com/2019/04/15/world/europe/notre-dame-c...

> After construction had begun, flying buttresses were added to the design of the cathedral.

IIRC, they also upgraded the first set with sturdier ones in the 14th Century.

Why didn't anyone tell David Chipperfield?

https://de.wikipedia.org/wiki/Datei:Berlin_Neues_Museum_001....

https://de.wikipedia.org/wiki/Datei:Neues_Museum_06b_Treppen...

This is the first time I've heard of your interpretation. I'm afraid it's not as standard as you think.

Thanks for the characteristically rude HN assumption that I don't know what I'm talking about.

I know all about Chipperfield, at least to the extent of having seen him lecture about his work in Berlin. He was inspired by Dollgast's work http://www.prewettbizley.com/graham-bizley-blog/dollgast and to be honest I don't see the contradiction with what I said. Not everything Chipperfield did in the Neues Museum falls into the category of "restoration" but the parts that do absolutely follow this principle of discreet but identifiable replacement.

Chipperfield on Dollgast: http://www.youtube.com/watch?v=RfizDUjvomA&t=36m56s

See especially the bit at 38:30 where he talks about not confusing the original with the new (in archaeological reconstruction).

Here also is a reference to a 2013 book that says almost exactly what I said: https://books.google.ie/books?id=ddTZAAAAQBAJ&pg=PT366&dq=br...

Please don't further pollute the already toxic environment on HN by assuming the person you are talking to is incompetent, acting in bad faith, or knows less than you do.

I appreciate your knowledge on this topic and your many knowledgeable, polymathic even, contributions to HN. All of that is fabulous. It's just what this site is for. I'm afraid, though, that you added more toxicity just now than anoncake did. I don't see an assumption there that you don't know things—only a question. At minimum, that would be the charitable interpretation à la the site guidelines: "Please respond to the strongest plausible interpretation of what someone says, not a weaker one that's easier to criticize. Assume good faith."

I think the phenomenon here is how all-too-easy it is to add to toxicity while trying to defend the environment (and oneself) from toxicity. A lot of us do this. I do it myself, and have constantly to learn not to.

https://news.ycombinator.com/newsguidelines.html

Dang, you're good. Thank you.

Thank you. I wondered if my phrasing was that bad.

>I don't see an assumption there that you don't know things—only a question.

The initial poster used a mocking phrase "Why didn't anyone tell David Chipperfield?" This is not "only a question"--it's an obviously sarcarstic question. Not claiming that OP's post is justified or my post is not off-topic, but IMO if you want to intervene from an understanding angle, you should see it from GP's perspective as well

> France signed the Venice Convention in the 70s

Not only that, according to a friend the French laws about replacements are so harsh, that he:

* would have to use handmade wallpapers

* was not allowed to replace a very thin outer door with a slightly thicker one so that he could have steel bars run in the door to provide adequate security (he would not have been allowed to drill the holes the bars lock into on the other side of the frame either)

He sold his house after realizing that there is no way around these rules (and he worked in French bureaucracy all his life).

PS: IIRC it was a small 17th century hôtel particulier in a town some hours from Paris, off the tourist track.

Macron is actually trying to pass a law to make an exception and loosen the rules for the Notre Dame restauration.

The official reason is to make it faster, but if he/the government wants to make it different, they can change the law as they control the Assemblée Nationale.

The French Senate have already made the decision that Notre Dame needs to be rebuilt exactly as it was. So, the discussion of changing the cathedral is moot anyway.

-> https://www.smithsonianmag.com/smart-news/frances-senate-vot...

That's just talking about the spire. As for the rest of it, the bill includes the language "If the [conservation team] uses materials different from those in place prior to the disaster, it [should] publish a study giving the reasons for these changes."

Seems to me like "We're using steel instead of wood for non-visible parts for reason of it not being flammable", that would be a good reason.

The Venice Charter is a set of conservation and restoration guidelines, not an international treaty with the force of law. There are other ICOMOS doctrinal texts,[0] as well. The 2003 ICOMOS charter Prinicples for the analysis, conservation and Structural Restoration of Architectural Heritage declares "The choice between ?traditional? and ?innovative? techniques should be weighed up on a case-by-case basis and preference given to those that are least invasive and most compatible with heritage values, bearing in mind safety and durability requirements. (3.7)"[1] Article 10 of the Venice Charter also states that "Where traditional techniques prove inadequate, the consolidation of a monument can be achieved by the use of any modern technique for conservation and construction, the efficacy of which has been shown by scientific data and proved by experience." There's no single answer here, just a very loud debate to come that will be shaped by guidelines and experience.

The fire risk of timber roofs in medieval cathedrals is well-documented throughout history. Given that risk, the lack of fire breaks in the cathedral's attic, etc., there's an excellent argument to be made for deviating from the historical design for the reconstructed roof's internal structure. Reconstruction isn't about just restoring what's been damaged or lost, but also protecting the structure for future generations. Weighing possible increased fired safety over the course of centuries against restoring the original design is going to be a major point of debate during the planning stages, even in light of existing restoration guidelines. That's setting aside the possibility of design changes needed to use cross laminated lumber as a substitute for old growth oak timber that's no longer available, or worries about the adhesives in failing over the course of a few centuries in a load-bearing structure. That's a scenario with very unique challenges.

0. https://www.icomos.org/en/charters-and-other-doctrinal-texts

1. https://www.icomos.org/en/about-the-centre/179-articles-en-f...

I'm not really seeing how something signed in the 70s is going to prevent France from repairing a devastated building, that is French to the core and located in the French capital, however they see fit. If they come out and say it makes sense to use non-flammable materials for the reconstruction (which would make sense), who in the world is going to stop them exactly? Notre Dame was already damaged by the fire (which this treaty couldn't prevent), and now it's about repairing it.

The people with the power to change the treaty don't materially care about the restoration and the people in change of the restoration don't have the power to change the treaty.

Without some huge effort to range awareness in favour of changing the Notre Dame for the better, the treaty will remain and those in charge of the repairs will have no say in how they go ahead.

Unless of course they were to withdraw from the treaty ...

Tis the season.

The thing is nothing is stopping them from ignoring the treaty and just doing the restoration anyway; no one is going to embargo or declare war on France over medieval architecture

And especially not if done for the entirely reasonable reason of "The wood burned the last time, so this time we're not going to rebuild the internal parts out of wood."

It's also less clear that this treaty applies to rebuilding work; the original intent appears to be preventing unnecessary changes.

They've recently rebuilt the roof of the "collège des Bernardins", also in Paris and as old as Notre Dame, using steel beams and titanium tiles...

Doing the same for Notre Dame would be sensible.

They will do as they see fit, and rightly so.

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