This is Mr Benjamin Mouton,
he was the main architect of Notre-Dame for 13 years, between 2000 and 2013. Good evening and welcome, Mr Mouton. We have many questions for you, and the first one is the following: Are we sure, tonight, that Notre-Dame, that the building is safe, that what remains will hold on? No. No, we aren’t sure. We are not sure because, the fire is extinguished, but there is a lot of soaking wet burned timber on top of the vaults; and on reaching the vaults, they made an impact, thus shaking these vaults. I was looking at a picture showing the crossing vault; it was known to be the most fragile one. We’re going to see it again And then we have had burning wood pieces on the stone, heating the stone, and at 900°C it turns into lime, thus loosing its mechanical properties. The point is, the highest points of the vaults are the most important for the vaulting system. On top of that there is all the water from the firemen’s hoses, which, with the remains of the timber, creates an overload on the vaults. We’ll be able to be more precise on the state of the Cathedral once we have it covered up, gently so as not to cause any reaction, and we can examine the vaults. Before that, we can not say much. Were you surprised by… not by the fire, but by the way it became so large, so quickly? Totally. That is incomprehensible. Incomprehensible? I am baffled. It is very ancient oak… … and it seems to have burned like matchsticks, as if it was another type of wood, one very unstable and flammable. I don’t understand this. I really don’t understand this at all. It is remarkable. You don’t see what could be the origin of this? The origin? The origin of the fire? No, no idea. The origin itself, we don’t know yet, the preferred line of inquiry is an accidental cause, but you say the propagation is astonishing… Yes, the propagation is extremely puzzling. It started of course from the crossing, then fire propagated above the choir, the nave, the transept- We hear many comments saying that the “forest”, this very large, very important, extended area of timber frame that this timber framework can burn like kindling, you don’t agree with that, you say that this type of wood doesn’t burn like that…? No, it doesn’t. You know, 800 years old oak, it is very hard, and you can try to burn it – I haven’t done so but oak… Old oak, it’s not so easy.
You’ll need a lot of kindling to succeed. I don’t know if there was kindling… All jokes aside, I am really baffled. So, where does this line of thinking leads you ? What hypotheses do you hold? … er… I don’t see one that I can tell. What hypotheses could be told? That… … … …That it was FAST. That something else could have been done
so that it didn’t go that fast? I am speculating. You know, we’ve worked in Notre-Dame, just before I retired, around the early 2010s, we’ve renewed the whole electrical system of Notre-Dame.So there is no short circuit possible. we’ve remade, according to current standards, and pushing VERY far, all the fire-detection and fire protection system of the Cathedral, with elements such as measurement indicators, aspirating smoke detector, etc, allowing to detect a fire outbreak; On the ground floor, you have two men, who are there 24/7, to go up and check any warning, and call the firemen as soon as needed They are always all the time? Yes, at all times. [inaudible at beginning]
(?)Could there be (?) a fault in the warning system ? Is it possible? Everything is possible. Everything is possible. I personally don’t see… because it has been such an immense work… .and on all these historic monuments construction sites, especially in Notre-Dame, there are such constraints, such a frame of technical standards, QC etc that is very important, that you don’t see anywhere else. Quite formidable. So, here, I am quite flabbergasted. And, during the 13 years you have been the main architect of the building, you didn’t encounter any… … there was no fire outbreak, it never happened? No. Mmh. Very well. One can see though that restoring work on a historic monument so ancient increases the fragility of the monument itself, and an additional issue is surveillance of this type of construction site, it is really mind-boggling to hear that we are told “there was no more worker on site” [at the time of the fire outbreak] In other words, there was no one there to keep an eye on such an important site even though it is clear that such a restoration site in such an historic monument, it is difficult to understand why there was no compulsory strict surveillance at all times, 24/7, so I think that the law on restoration of historic monument has to change… for it looks like a deficiency, at least regarding surveillance. You may be right, but I’ll add two caveats. First, when the workers leave the site, general surveillance resumes. It never really stops in fact, it keeps on. So there is no difference… But it is not suited to historic monument renovation works, it is still the 2 men on the ground floor, 24/7… Yes, but with all the measurement and detection gear in the attic space. I should add something: these detection sensors in the attic are powered in such a way that there is no risk of a short circuit, all junctions are in the staircases, away from the fire doors. The second comment I had is that, and that may surprise you, when you look at statistics on damages in the construction industry, historic monuments are close to nothing. So… That’s because there are very few historic monuments, quite simply? No, no. Because these sites are under very high surveillance. Highly regulated. With drastic conditions regarding protection, surveillance, etc. So there, I think that… the idea that a restoration weakens the monument, I don’t bel- Mr Mouton, what you describe leads to the assumption that… someone may have caused the conditions of the fire…? I will refrain from making any assumption. It is very sensitive/difficult and, of course, … In the current situation I don’t think we can… We’ll see later what’s the justice impression… and the beginning of the investigation. For now this hypotheses is ABSOLUTELY not the preferred one. (First Franck, then Juliette) Just a question – the assumption that there were 2 initial fires, is it true or not? I heard about this from my colleague, Philippe Villeneuve, who is the Historic Monuments head architect, and who approved my participation to this interview, he told me knowing only about one fire outbreak, at the junction where the roof from the nave meets the roof from the transept. He told me, only that one.
And he added: there was no work site at that location. There was no work site there ? There was no work site there. So, your successor told you that the fire broke at a location where there was no work ? Indeed. There was no worksite. Well, that’s another aspect… of course… Interesting. Franck? I have a question, I don’t know your trade of course, but, when you see such a timber frame – “the Forest” – I know that on some building, my house for example with its thatched roof, there are some fire-retardant chemicals to protect, to slow propagation, and you are surprised by the fire propagation speed, was the timber protected by such chemicals to protect from propagation, was it done, or doesn’t it exist? I’m wondering, wasn’t there something to spray on the timber to slow down propagation in case of fire? For these chemicals to be efficient, they have to penetrate into the wood. Try to get that into ancient oak.
Any chemical – insecticide, fungicide, or this. It doesn’t work. It’s not possible.
If it could have been done, it would have been. Juliette? Just a note. This is a building so old, undergoing works, and for which, in the end, maintenance budget available was relatively low, so it seems almost a miracle that there was no more fires like that, in the end, over the centuries that Notre-Dame de Paris has been there(…) The second thing is that, after all, the fact that all the work of arts that could be evacuated were evacuated, that there was no one wounded, no fatality, no one says it, but it shows there was great responsiveness from civil security, from law enforcement, probably from the watchmen, preserving what could be preserved, so, after all, I appreciate how such a fire was quickly, relatively quickly contained, yes there was of course the Parisian firemen, civil security, probably too the Cathedral staff, so I find all of this admirable, but… well, of course, this doesn’t contradict anything you’ve said. I agree fully with you that conserving this exceptional timber frame, such a witness of carpentry art from the end of the XIIth century and from the beginning of the XIIIth century, seeing the links, the influences, the improvements developping during construction of the nave, it’s a fascinating display, one which exist – which existed – nowhere else. And the fact that it was still there in 2013 when I left, and until the day before yesterday, it is true, it seems like a miracle. But this miracle… I do not dare say it tricked us… but maybe we said too soon “we did everything we can, it’s going to be OK”. But in the end… there is no such thing as zero-risk. One last question, Mr Mouton, what is your state of mind? I’ve been asking everyone tonight, are you rather relieved tonight ?
or, err…, distraught, appalled by what has happened Relieved ? How would I be?
No, I am not relieved at all. Because yesterday night, at one point, it was feared the whole building would… mmh, no, I don’t believe- You didn’t fear that? No, I didn’t. The two towers at the West end, where the belfries are, are separated from the nave by walls that are pierced by very few doors. so fire propagation to these two towers was extremely unlikely. On the other hand, if there had been fire there, there are 8 bells in the northern tower, and 2 in the southern one, including the great bell, Emmanuel. And there, it would have been an horrible disaster. Fire was nowhere in the towers? Not that I know of. It could have propagated through the abat-sons, but apparently these are in good shape, they have not been burned. So why do you say you are “not relieved at all” ? Because I don’t see how I could be “relieved” after this fire. Even if I tell myself “oh, we haven’t lost everything…” I can not be relieved, sorry. Thank you Mr Mouton, for joining us tonight.