>b) Make any repair work obvious (don't try to pass new fabric off as original)
>c) Repairs should be reversible.
I don't think everyone agrees to this. At least, I don't. It's absurd to put a wooden roof back onto a structure seriously damaged by a roof fire. Whatever goes up there should be non-flammable. At minimum something that won't crash in the roof again in case there is a fire. Rebuilding it in the same fashion would be monumentally stupid.
Setting aside the safety issue, I go back and forth if it should be restored in exactly the same way. Notre Dame has been modified and improved over time and I don't necessarily think it needs to go back exactly the way it was. Like the glass pyramid in the Louvre perhaps modern materials can be an improvement.
That's part of the building's history now, for better or worse. I expect Viollet-le-Duc's work will be restored, even if some people think he was crass.
This whole issue isn't something that can be resolved easily. It's important not to look down on the activities of repair and maintenance. They might not be as glamorous as artistic creation, but obviously there's love, skill and creativity involved in repair as well. We need more of that.
A bad intervention by a currently successful artist or architect would be nothing to be proud of in future years. "Move fast and break things" is not appropriate in this situation. It's not as if a repair job involves pure boredom, imitation and humility—those craftsmen will be expressing themselves and their passion just fine.
The 19th C fixation on romantic originality, on the heroic artist? We don't need that. Not to be cynical about the state of architecture, but we can't match even Viollet-le-Duc's iffy work now. We need to shift into a different mode with more emphasis on preserving building skills and historical artefacts than on altering them to suit the whim of the people who happen to be alive now.
Music is the same, painting is the same. A piece of medieval music can be perfect on its own terms. It wouldn't make sense to say that electronic music is better because the tech is more advanced. Artistic value and technology are totally separate issues.
Painting materials have evolved and become cheaper, making art more accessible to the average person, expanding the artistic landscape.
These things have not stayed the same. It's odd that you think they have.
What I'm saying is not an unusual opinion. I mentioned electronic music, so it should have been obvious that I'm aware that "things have not stayed the same". But the point I'm trying to allude to is the fact that art is an expression of the human spirit, and because of that, it doesn't advance like science or technology.
Here's an example of someone writing in the Guardian:
"It was a year of revelations. The oldest portrait in the world – carved out of mammoth tusk 26,000 years ago in Moravia – had a long slender face, almond eyes and a rueful half-smile: just like a Modigliani. She came to the British Museum along with Ice Age drawings and sculptures so superb they have never been surpassed, proving once again that there is no progress – only change – in art."
From https://www.theguardian.com/culture/2013/dec/22/art-review-2...
Or, on a slightly different point: "It is obvious that art cannot teach anyone anything, since in four thousand years humanity has learnt nothing at all." (Tarkovsky)
Tarkovsky obviously isn't denying the growth of scientific knowledge. He just thinks there are aspects of human nature that only change slowly, if at all, and that those aspects are more significant than the accumulation of scientific knowledge and all the changes that brings about.
Progress in nuclear physics hasn't got a lot to do with progress in human politics and (dare I say it) justice/peace.
Construction technology is similar vis a vis architecture. Revit, 3D printing and advanced materials aren't an automatic ticket to making architectural work that's as good as or better than Angkor Wat. I mean, just what materials you build something out of, and what technologies you use, both obviously contribute to the particular artistic problem that the architect solves. But someone working with very limited technology can produce a fully developed artistic masterwork under those constraints. That's just something we know empirically from looking at the art of the past.
So this is more about never being complacent that what's being made today will match or surpass the artistic high points of the past. That's what the "no progress" concept means to me. There's a level playing field—none of us has any kind of technology that means we can unthinkingly produce work that compares well with renaissance masterpieces. The real picture is quite a bit more depressing that that...
There is beauty in reconstruction, and calling it 'fake' misses the point.
a) Replace like with like (don't change materials or construction techniques)
b) Make any repair work obvious (don't try to pass new fabric off as original)
c) Repairs should be reversible.
It's a complicated field, but the general spirit is that when a building needs to be repaired, you try to make the new elements match as closely as possible to the way the structure was when it was first built. You don't say "we know better than the medieval masons, so we'll use reinforced concrete instead of stone" because that wouldn't be a restoration. It would turn the building into a hybrid of old and new technology, when what everyone wants is to experience the old way of building.
There's also an element of arrogance in trying to improve on medieval architecture—most people would agree that architecture, as an art, isn't something that progresses inexorably like science. The cathedrals are already as good as architecture gets. "Updating" a medieval structure to use the trendy structural technologies of the 21st century is a barbaric idea, because it is literally a case of destroying or interfering with an irreplaceable artefact.
Obviously, not every old structure has to be treated with kid gloves as a priceless artefact. But I hope you can see what I'm getting at when I say that "best practice" in building conservation means not acting as if you know better than the original builders. It's a case of respecting the original design and not messing with it for the sake of employing modern technology.