Let’s fix up Notre Dame with concrete and steel: but enjoy the sunshine while it lasts

_106468565_hi053452713.jpgSo, here’s a story. On 15 April 2019, when the roofspace over the crossing of Paris Cathedral caught fire, I was in a pub in east London having a burger. My initial reaction was not one of anxiety for the 12th-century Early Gothic church, with its splendid 13th-century Rayonnant superstructure and rose windows with contemporary (if VERY restored) medieval stained glass, but instead a slight feeling of dismay of how long this would mean the building would be closed and how much it would cost to replace the roof. It was also a great shame to lose the crowning achievement of the restorer Eugène Viollet-le-Duc, his magnificent Neo-Gothic crossing flèche, albeit mere days after all the statues had been removed from it for restoration. Anyway, then I went off to watch Kubrick-themed Italian thrash-metal revival band Ultra-Violence open for Wisconsin death metallers Jungle Rot without that much worry.

Point cloud-based cross sectional rendering of Paris Cathedral by Andrew Tallon, so you can see the difference between a ROOF and a CEILING
You see, not to be all Dr Know-it-All here, but what looked like ABSOLUTE DESTRUCTION to most of you looked like what it was to me – the wooden roof burning off the top of a stone building. It’s like a golem’s hat caught fire. One of the first things to get going in architecture is understanding the difference between a roof and a ceiling. Michelangelo did not paint the Sistine Chapel ROOF. If you go up to the bedroom on the top floor of a house, you don’t see the ROOF. You see A CEILING. You only see the roof structure of most houses when you go into the attic.

york minster.jpg
A fire in the choir of York Minster in 1829 started by a disgruntled anti-Anglican cleric destroyed the medieval wooden ceiling and choir furniture of the cathedral

Notre Dame, like nearly every French cathedral (and most English Gothic ones) is covered by a high stone vault that makes the roof completely invisible from the interior. Essentially vaults are stone arches in three dimensions, and are nearly as stable as arches in a single plane. At least part of the reason that they were commonly employed in Gothic architecture was to make sure that the interior, and all its furniture and fittings (not to mention people) were protected from the biggest fire hazard – the roof structure – from crashing down to the floor as soon as it set ablaze. Places like York Minster, that always had wooden sham-vaults in their central vessel (which for various complicated reasons is unusually wide and therefore difficult to vault in stone), feel the pinch as a roof fire can be almost immediately catastrophic, as was the case in 1829 when Jonathan “Mad” Martin set fire to the choir furniture which ultimately destroyed the Minster’s choir roof and ceiling (although in the fire of 1984 in the south transept, the outer bay of the medieval wooden vault was purposely dropped to the floor so the firefighters could drench it and stop it spreading to the next bay).

When people reported that the rose Windows had exploded on that Monday night, and all the medieval stained glass of Notre Dame was lost, I literally didn’t believe it. I mean like, you might as well have said that Brian Blessed turned up and blew the fire out. Because it’s almost unthinkable that a roof fire (from which heat travels up) is going to significantly damage a window well below it. And yes, I was right. What had exploded were the smaller rose windows that allow light into the roofspace, which of course, have always had plain glazing, because no one looks through them except workmen.

SEI_62857434-e1555488108249Let me admit that perhaps I should not have been too blasé. The high vault of Paris Cathedral collapsed in three places on 15/16 April, two cells in the nave (half of first bay and half of second, along with a hole in the adjacent north cell), one in the north transept, and most notably of all, the entire crossing. Here it is rendered in red on a ground plan.


Note the outer ring of vaulting is the outer chapels, the next two are the double aisles, and there are also vaults in the gallery directly above the inner aisle. None of these lower roofs appear to be affected, the high roof is a long way from them after all.

It does not seem to be widely reported that the crossing collapsed sometime in the morning of the 16 April, as there was an initial photograph by a reporter showing it to be largely intact, except flames visible through the central boss.

Whether this was due to the impact of the flèche falling down, or the extra fuel it provide to raise the heat there, I don’t know. Vaults are quite sturdy, but they aren’t designed to take much weight from above – hence why you usually never walk about on top of them and have suspended walkways over them for regular access. But as the largest vault with the least ribs in the cathedral, it’s probably the most vulnerable. It’s worth saying that the crossing of Rheims completely collapsed too after the roof burnt off in 1914, but then this was due to bombardment rather than simply fire.

Rheims Cathedral, looking W from on top of the choir vaults, 1919

notredameinterior1704-0.jpgThe interior of Notre Dame currently has piles of debris under the three vault collapses – the charred remains of the roof and flèche, and the masonry of the vaults. Sensibly it has been left untouched, as it seems plausible some of the voussoirs of the ribs could be reused in reconstruction of the vaults.

However, it seems that absolutely no art has been damaged, not even the Baroque canvas oil paintings that hung on the walls of the transepts. Vaults collapsing no doubt makes a big crash with a lot of dust, but there’s no domino effect with the adjacent bays falling as you might expect (the support is from the side walls, not the adjacent vaults, as many single bays of vaulting in ruined abbeys attest).

assisi roofspace.png
The crossing of San Francesco, Assisi after 1997 earthquake. The roof is supported by quadrant arches of 15thc masonry, with purlins of reinforced concrete from 1953.

Three cells fell out of the vault of the Basilica of San Francesco in Assisi in 1997 during an earthquake (one on top of 4 people who’d entered the building after an initial smaller quake the night before), and apart from the frescoes directly painted on their structure (Matthew the Evangelist by Cimabue and St Jerome by the Roman Masters of the St Francis Cycle), but somewhat surprisingly, there was essentially no damage to the famous frescos of the Life of St Francis on the walls right next to the site of the collapse.

Assisi plan.png
Plan of vault collapses at San Francesco, Assisi in 1997

Anyway if you think a few vault cells falling down is bad, you should see Soissons Cathedral after the second Battle of the Aisne in 1919.

(yes, that is TWO WHOLE BAYS of the early 13th-century nave destroyed and subsequently rebuilt)

What’s been more depressing than the Notre Dame fire itself is the aftermath. The alt-right hate crew roll in to blame the Muslims (for, um, sneaking inside the roof space to start a fire that hardly damaged the structure at all ah yes, much more likely than an electrical fault: like and subscribe). Floundering President Macron seizes on it to try and rally his gilet-jaune agitators into some sort of patriotic common cause by promising it’ll all be fine in five years. Billionaires donate a bit of pocket change at a 95% tax deductible rate to get themselves on the golden wall of donors when they should simply be paying more tax on their obscene wealth. Saddest of all, a load of spreadsheet architectural firms get free publicity by doing stupid renders where they put a swimming pool on top of the cathedral, or a glass roof to let light in, revealing that they don’t even seem to understand the concept of a vault. The hack journos lap all this up, and don’t try to talk to the people hard at work consolidating and assessing the structure. I’m not even going to dignify these starachitects’ horrendously egotistical self-promotion by making fun of any of them directly. This video does it much better than I could.

So what should be done? First and foremost, a roof is practical – it simply a frame designed to angle a covering of waterproof material to throw off precipitation. To nearly every visitor to a cathedral, its structure below the shingles, tiles or lead is invisible to them. Most people do not think of the roofspace above them, because it is, essentially, only accessible for maintenance purposes. The French often refer to cathedral roofspaces as “la Forêt” (the forest) because of the maze of timbers (for the avoidance of doubt, this was not specific to Paris, but generally used in most French church high roofspaces). You generally walk in these attic spaces on suspended walkways over the vaults, and there is little natural light except from windows in large end gables, and small lucarnes in the roof.

The (former) high roofspace at Paris Cathedral
When you go to Chartres, do you realise the roof burnt off in a similar work-based accident in 1836, and was replaced by an ingeniously modern structure of wrought and cast iron, drawing on the recent technology some of the most recent iron bridges by Thomas Telford in the west of England? It’s really rather artful.

chartres roof space
Chartres Cathedral, roofspace, 1837–9 by Théophile Mignon

Rheims Cathedral had its whole roof burnt off during bombardment in 1914. Do you notice now that the roof put on the 1920s and 30s is made of reinforced concrete? Well, only if you go up one of the spiral stairs through the whole height of the walls and walk round the roofspace, you don’t.

reims roofpace
Rheims Cathedral, roofspace, 1919-38 by Henri Deneux.

That’s why to me, the thought of using “new-craft” talent and traditional oak to replicate the original roof is pointless and little bit silly too. Medieval roof structures are almost textbook tinderboxes of large and small timbers, and why in the Middle Ages roofs burning off churches was a relatively common occurrence, especially since they didn’t have lightning conductors (or indeed, dodgy wiring). It’s interesting to see that although the roof timbers were incinerated overnight, the steel scaffold at the heart of the blaze that had – ironically – been constructed around the flèche for its restoration, has only been damaged by its westward fall, the rest is basically fine. Wood burns well below the melting point for even basic metal. I’ll leave it to the professional engineers to design, but not creating the new roof out of a mixture of light-weight concrete and steel strengthening seems like a cut and shut case, really, unless you want to have a Glasgow School of Art on your hands when it catches fire again.

View south across the collapsed crossing from N transept. The flèche fell to the right of the picture.

14th-century iron ties on the late 13th-century flyers of Beauvais Cathedral
Metal has been used for a VERY long time in church restoration. Beauvais Cathedral, which had some vault pockets fall out in 1284 necessitating a change of plan on the part of the builders, has iron ties between the buttresses which are from at least the 14th century, and also iron clamps across the stones in the redesigned high vault itself. Ruined abbeys, for instance Whitby in North Yorkshire, are only still standing to the level they are because the men from the ministry inserted iron rods into the wall cores in the early 20th century. Does that spoil them for you? Nope, because I bet you didn’t have a clue before now how much work people do to keep these ancient buildings here for you to look at.

Notre dame flecheSince we have the original statues in storage, Viollet-le-Duc’s timber and lead flèche ought to be reconstructed to his original designs. It’s a slap in the face to the man who had the vision to create the Notre Dame that Paris could love again after the city had abused the structure so appallingly in the Revolution and Reign of Terror if they don’t. We have his original plans, it shouldn’t be too hard.

Removing glass from the choir clerestory at Notre Dame, early May 2019

However, it seems to me that the one thing the 19th century got wrong was the glazing. Nearly every window in Notre Dame was filled with stained glass during Viollet-le-Duc’s surveyorship, and while this was no doubt the situation in the Middle Ages, this modern glass is severe and flat, rather than delicate and jewel-like like genuine medieval glass (the original medieval glass is mainly in the three great roses, but an awful lot of that is filled in with the same sort of gaudy bubblegum 19th-century stuff). Currently, the team of conservators have removed all the glazing from the clerestory, and it looks rather delicate and lovely. Paris Cathedral was a very difficult building to actually examine from the inside. You were almost looking at the lighting system more than the structure itself. But since the crossing vault has gone, wow, in photos, it looks FANTASTIC.

It was all very blue, wasn’t it? Well, just about every window had coloured glass in it, even those at the back of the gallery spaces you can’t see from the floor. Also awful recent ideas such as illuminating the vault bosses with spotlights made the whole lighting system of the interior very distracting, unreal, and sterile. A church interior should change with the passing of the day. Notre Dame always looked the same: like being in a gloomy jacuzzi. But with real, unfiltered sunlight passing over it, it actually looks alive again! How ironic it takes the roof burning off and the crossing collapsing to make me say that.


Now, I’m not saying they should put a lantern that opens up the roof over the collapsed crossing, like Ely Cathedral. That would probably be an intervention too far (but you could bet the Middle Ages would have a crack at it). But do let the sunlight continue to fall across these stones and get the endless Parnassian passages of Victorian-Era glass out to let the clerestory do what it’s supposed to do – be a clear story. The building deserves it. But as for the roof, I take the words of Billy Gibbons from the opening track of ZZ Top’s 1990 album Recycler.

Concrete and steel: hey baby, what’s the deal?

(Note on picture credits. Featured image was posted by the Cathedral themselves on their Twitter account. Collapsing spire from a video distributed by Reuters. The interiors and the shots of the burnt-out roof were taken by Thomas Goisque around two weeks after the fire. You can see – and use – all my pictures of Notre Dame’s interior from summer 2016 on Flickr)


    • Also I always thought he got up on the roof to set the fire. Turns out he just started a fire in the choir stalls which must’ve gone upwards. Oops, corrected. 1984 fire was roof primarily though, probably started by a lightning strike

      • Actually it was God’s revenge for the appointment of David Jenkins as the Bishop of Durham. Or so it was said. You’re probably too young to remember, but there were people at the time who were (apparently in all seriousness) proposing this.

  1. Thanks for the very enlightening post, sir. I was really taken aback when I saw what was going on and, being an idiot in architecture, was ready to write off the good old Dame. This post has given me confidence it won’t be the case and hopefully a better roof will be built.

    Interesting music choices I’ve to say!

    • Not sure if you’re referring to the extreme metal or mid-period MTV-ready ZZ Top (of course their ’70s output was superior but still have a soft spot for synth phase. Don’t get me started on how underrated Rhythmeen is)

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