I had a few questions today from my Introduction to Humanities students about the fire at Notre Dame Cathedral and how exactly the fire affected the building, and I thought I would post my explanation here in the hopes that it will be helpful for others who may be confused. Before I begin, I’d like to provide a couple of caveats to this explanation. First, the investigation is just starting, and no conclusions have yet been reached. I’m basing this on the images I saw on TV and online during the conflagration, combined with my knowledge of Romanesque and Gothic architecture. Second, with full apologies to the architects that created wondrous buildings so that medieval communities could better worship God, I am going to use the prosaic terminology of modern commercial architecture to describe one of the most glorious architectural creations of Western Christendom (scholars of medieval architecture may want to look away).
I think that much of the news coverage of the fire at Notre Dame was confusing because the newscasters were using terminology that neither they, nor their audience, completely understood. When they reported that the “frame” was completely engulfed in fire or that officials were worried about the “vaults,” they may have confused people in America that are accustomed to referring to wooden frame construction in which the “frame” is essentially the skeleton of the entire house and referring to “vaults” as places where money and treasure are stored. The Classical architectural meanings got a little lost in the tension and horror of the fire, and I hope to rectify that in some small way.
Let’s begin with an example that most Americans are familiar with: the commercial building with a drop ceiling. These are the structures that have ceiling tiles held up by thin metal supports. If the ceiling in question is on the top floor of the structure, there may be an attic, or at least a crawl space above them. If the roof of the building is peaked (if it forms a triangle), then there will be wooden rafter in the attic to provide the structure on which the actual roof and its shingles are placed. Ok, with me so far? This is where my comparison gets a little weird. For purposes of understanding and discussion, let’s equate the “vault” the newscasters kept referring to with the drop ceiling (albeit a drop ceiling constructed out of stone blocks). In the same vein, let’s refer to the arches that make the vault possible as the metal supports which hold up the “tiles” of the drop ceiling. In the case of Notre Dame, these supports are also stone. This will be important in a minute. The “forest” of trees (I believe it was about 13,000 trees worth) which made up Notre Dame’s frame and supported her roof can rather easily be equated with the rafters in a modern building. This would make the space they created the attic. Lastly, instead of asphalt shingles, Notre Dame had a lead roof. Ironically enough, this should have made it fire resistant at the very least.
Now that the modern equivalents I’m using are hopefully clear, let’s talk about what happened during the fire. We do not know how it started or exactly where it started. Apparently, the first responders to the scene could not find the fire. French authorities are investigating. From the many, many videos taken during the fire, it looked like the flames first appeared near the spire. Since the spire presumably was placed into the roof (thus making a hole in the lead roofing), that could have allowed the fire to breach the roof. It is also possible that the fire began under the roof, in the rafters. In any case, the bulk of the fire attacked those rafters with a frightening enthusiasm and set the attic on fire. This in turn melted the shingles. This sounds terrible, and it is; but it was not as destructive as it would be in a modern building. Where a modern building’s ceiling tiles are flammable, the “tiles” of Notre Dame Cathedral are not. Remember when I said that the fact that they are stone would be important? Now’s the time. The burning attic landed on the “ceiling tiles” and largely remained there to burn. It did knock a few holes in the “tiles”–presumably when the spire fell. However, the stone “ceiling tiles” largely kept the fire out of the interior spaces of the cathedral. This is why so much of the interior is miraculously intact.
So, that’s the end of my analysis of Notre Dame’s architecture in terms of modern construction. Now, let’s get a little more Medieval. Because of when it was built, Notre Dame has both the thick walls of Romanesque architecture and the flying buttresses of later Gothic architecture. The fact that the walls are so thick is probably a major factor in the fact that those walls are still standing. The flying buttresses (the “legs” that protrude from the exterior of the building) are there to support the interior arches, including those that are holding up the vaulted ceiling. These two factors combined together to create a very strong building. While I do not pretend to know anything about the affect of fire and high temperatures on the structural integrity of stone, I think the fact that the walls (and the towers) are still standing is a very good sign. Medieval craftsmen more than 800 years ago successfully created a building that managed to survive a devastatingly powerful fire in the 21st Century. Those Medieval craftsmen deserve our applause and our thanks.
I hope that you found this analysis at least a little bit helpful in understanding both the tragedy and the miracle that came from fire at the Notre Dame Cathedral. The fire was truly terrible, but it could have been so much worse. France will rebuild, but it is wonderful that so much of the original structure has survived.