[theoh]

This idea (replicate old structure in a new material) is not really a thing in building conservation. One reason for this is that the dimensions of structural elements are a function of the properties of the original material: it just doesn't make sense to replace a timber beam with a steel one of the same dimensions.

The presence of timber in a historic structure obviously makes it less durable and fire-resistant, but it is authentic, and that is something that is taken very seriously.

It's like an old recipe, an old painting, or an old piece of music. Nobody who is seriously engaged with those things believes in improving them by substituting modern high-tech elements in the course of recreating/restoring an original.

[burfog]

We sure do.

In the old recipe, we replace the margarine with butter. We always replace the passenger pigeon, typically with chicken, but there may be higher-quality substitutes.

If you want to paint in the style of Rembrandt, you can do that without deadly toxic vermilion.

Music by Mozart and Berlioz is not normally played on the serpent or ophicleide. We're even beginning the process of replacing the contrabassoon with the contraforte.

So likewise, if you want to replace a heavy roof that supports fire and insects and fungus, you would use materials without those problems. The steel replacement beam may be of the original dimensions if it is hollow, but that only makes sense for something externally visible. Unseen internal structure need not replicate the original.

[CydeWeys]

Fire protection systems are "inauthentic" too, and weren't included for that reason, with the end result being that we lost a lot more authenticity from the fire than would have been lost just by including fire protection.

Anyway, the wood is inside the roof. It's not even visible unless you go up into the attic. Would it really be such a big deal to replace it with steel trusses?

There's a role for modern technology to play in preserving older technology. Sometimes you need to retrofit the old stuff with the modern in order to preserve as much as possible over the long run. That's the case here.

[theoh]

Of course fire prevention measures can and should be taken in old buildings. Installing unobtrusive systems with the goal of protecting an authentic structure is routine, as is finding any and all possible ways of mitigating fire hazards without changing the character of the building.

This is a totally separate issue from the bizarre hylomorphic idea of replacing limestone and marble with granite(?!) and porcelain.

Here's an example of unseen functional reinforcement of an historic roof with a modern steel truss: https://www.julianharraparchitects.co.uk/st-annes-limehouse. This is a case of pragmatism and economy. It's a long way from completely replacing the roof structure with a modern solution.

The idea that is going around of rebuilding the roof of Notre Dame with diamond/Kryptonite/carbon fiber as a way of trumpeting how advanced we are is annoying. The consensus these days about restoration is that it should be about making humble, minimally invasive, economical changes. Just put things back in order. Put in a sprinkler system. This is not an occasion for making a tacky gesture that will only reveal how mediocre 21st C architecture is in comparison to medieval Gothic.

[burfog]

That steel truss is not a long way from completely replacing the roof structure with a modern solution. If anything it is more a departure from the original, which stood alone without help. It's not even an option for Notre Dame, because there is no longer any original wood or lead that one might want to save.

For a truly authentic roof appearance, only the lead surface matters. Lead is actually an awful substance to use though. It had cracked, letting in water to rot the wood. Swapping out that metal for one that is lighter and more durable would be sensible. I don't think it would be sacrilege to pick a better metal. Suggestions: phosphor bronze, surgical stainless steel, nickel, titanium, titanium nitride, titanium aluminum nitride, gold leaf over aluminium oxynitride, Monel, Inconel, cupronickel. Some examples here: http://finemetalrooftech.com/products/metal-shingles/

Limestone gargoyles only last a century. They aren't even old! They disintegrate due to the water flowing through them. The other grotesques, such as the chimera, were also pretty well disintegrated. Limestone is fundamentally terrible for long-term durability. The stone chemically dissolves, causing statues to turn crumbly and look melted. Glassy materials are far superior. All desired colors are available, so matching the original color is possible. You can go natural (white granite, black granite, etc.) or artificial.

There is nothing tacky about building with durable materials. Tacky would be like my house, with stucco over styrofoam, a very common construction method in the USA. Granite is the good stuff. Limestone is junk, almost as bad as my stucco over styrofoam.

[task_queue]

> It's like an old recipe, an old painting, or an old piece of music. Nobody who is seriously engaged with those things believes in improving them by substituting modern high-tech elements in the course of recreating/restoring an original.

Once knew a talented artist who painted in the style of the old masters and took pride in it. Substitution, or improvement, certainly exists in that school of thought, and in practice.

[theoh]

Evidently your understanding of "recreating/restoring an original" encompasses brand new creative works. That is not what is at issue here: Notre Dame is an original, irreplaceable structure.

[task_queue]

> Notre Dame is an original, irreplaceable structure.

And, from it's original state, it is gone. We cannot replace the irreplaceable, but we have the opportunity to modify it. Such is life.

[theoh]

This is gobbledygook. You say that the irreplaceable thing is gone and cannot be replaced, but also that somehow we now have an opportunity to modify it?

The cathedral is mostly intact. This is a repair job, just like a repair to an Old Master painting damaged by a vandal. A restorer wouldn't use the latest and greatest synthetic painting materials (acrylics or paints with synthetic binders) to repair an old master. They might use some new technology in the process, but they wouldn't treat the job as an opportunity to indulge their personal creative vanity and leave their mark on the painting. There is more than enough creativity and self-expression in the task of restoration.

[dragonwriter]

> The cathedral is mostly intact.

The original is not.

What is arguably largely intact (though, per TFA, that's true superficially but not structurally) is the result of multiple changes over a long period for a variety of different reasons (often in the context of repairs, but the past repair efforts weren't with an attitude of “restore the original with no artistic changes”.)

> just like a repair to an Old Master painting damaged by a vandal.

Except it's not like an Old Master painting, as the pre-recent-damage condition was he result of many different artistic visions at many different times, unless you are comparing all the past innovation to the work of vandals, not just the recent damage.

[SmellyGeekBoy]

I'm not sure why you've been downvoted for this. Notre Dame isn't just any old building, to carry on the art analogy it's in the same league as the Mona Lisa or Sunflowers etc.

Thankfully the French do have a very strong sense of tradition and cultural identity, something that's sadly being lost in most of the rest of the western world.

[toomanybeersies]

Notre Dame was not built in one hit, and then unchanged since.

Throughout its life, it has been added to, repaired, and modified as necessary.

[bluGill]

Nobody today would improve on the old. That wasn't always the case.

There is a lot of historical precedent for restorers "fixing" art. (Most often adding clothing to cover private areas). Since we now know the art by the "fixed version today there is the open question of if we remove the fix or not - either way we are destroying art.

[benj111]

A more recent example.

Winston Churchill's cigar has been edited from a photo before.

https://winstonchurchill.org/resources/in-the-media/churchil...