Kriston Capps is a staff writer for CityLab covering housing, architecture, and politics. He previously worked as a senior editor for Architect magazine.
Flames consumed the roof and spire of the 13th-century cathedral in Paris. The good news: Gothic architecture is built to handle this kind of disaster.
As the world watched in horror, Notre-Dame Cathedral erupted in flames on Monday evening in Paris, sending massive plumes of smoke rising from the Île de la Cité in the medieval heart of the city. Flames swiftly consumed the entire roof of the structure, and elements of the cathedral, including the central spire over the crossing where the transepts intersect the nave and chancel, collapsed into the blaze. One of the world’s greatest surviving works of Gothic architecture—a monument that had endured for more than 800 years—appeared to be in danger of complete destruction.
But it has survived: While the damage to the interior of the historic building is still uncertain, the fire did not consume Notre-Dame, according to authorities in Paris. The blaze stopped short of the two belfry towers that house the cathedral’s immense bells, the site immortalized by Victor Hugo in The Hunchback of Notre-Dame. “The worst has been avoided even though the battle is not completely won,” said French President Emmanuel Macron.
That’s the good news about Gothic architecture: It’s strong stuff, built to withstand even an inferno.
“It’s not that they’re designed to be burned down, but it’s designed so that if the roof burns off, it’s hard for [the fire] to spread to the rest of the building,” says Lisa Reilly, an associate professor of architectural history at the University of Virginia and a scholar of medieval architecture. “In the Middle Ages, the thought was that stone vaults [could be] used to prevent the spread of fire.”
In Notre-Dame, as in other Gothic cathedrals, the ceiling—what a person sees above when she steps into the building and looks up—is a stone vault. Above that area is the equivalent of an attic space. Heavy timbers hold up the roof above the stone vault. Typically in the Middle Ages, these wood truss systems would be covered in pitch to make them more resistant to rot (which also, unfortunately, makes them more prone to burning). But the stone structure itself is fundamentally fireproof.
The collapse of the roof is also not necessarily a threat to the integrity of the building. In 12th- and 13th-century buildings of this type, the walls are held in place by flying buttresses. The arch elements along the building’s exterior transfer the weight of the walls, the roof, and the stone-vault ceiling through the pillars of masonry that circle the building. “Basically, it’s a structural exoskeleton, with the support system largely on the outside of the building,” Reilly says.
There’s another bit of good news. Notre-Dame was an early Gothic building: Its cornerstone was laid in 1163 and it was completed in 1345. While pollution, weather, and politics all pose particular threats, the cathedral’s walls are more stout than they would have been had it been constructed 50 or 60 years later, Reilly says.
But those walls are still vulnerable to heat. The building is made of limestone, and if the stone cracks due to the high heat, that can cause the walls to destabilize.
Stone also makes extinguishing the fire a material risk. Firefighters don’t really have any choice, but inundating a stone building with water can compromise the structure. (President Donald Trump’s tweeted suggestion—flooding the cathedral from “flying water tankers”—would have been a bad idea.) According to Megan Rispoli, a project manager for Walter B. Melvin Architects, dousing the flames could have consequences, since the stone walls have absorbed heat from the fire, causing them to expand; bring down the temperature suddenly, and thermal contraction can shatter them.
“If you put really cold water on fire-heated stones, stones develop all sorts of cracks,” she says. “We’ve seen it happen with other masonry buildings that catch fire.”
Rispoli, an architectural preservationist, works primarily with exterior masonry. In New York, she has worked on the restoration of St. Patrick’s Cathedral, Grace Church, and other religious projects. She also specializes in ruins like the Cedar Island Lighthouse in East Hampton, which suffered a fire in the 1970s and has sat vacant ever since.
“The best-case scenario would be that the fire [at Notre-Dame] is limited to the ceiling and the roof structure,” Rispoli says. “A lot of the architecture below survives intact.”
As devastating as this fire is, Europe has been here before: Wars, accidents, and natural disasters have claimed a great many architectural treasures over the centuries. With their wood-framed interiors, large churches and cathedrals of the medieval era have long been vulnerable to conflagrations. In London, old St. Paul’s Cathedral, once among the largest in Europe, succumbed during the Great Fire of 1666. St. Martin’s Cathedral in Utrecht, the only example of classic Gothic architecture in the Netherlands, was destroyed by fires and repeatedly rebuilt until another element, this time a storm, caused its nave to collapse for good in 1674. (If it reads as though cathedrals are always bursting into flames, consider that history is long and cathedrals must survive a lot of it.)
Since the beginning of the 20th century, a few countries have worked hard on trying to bring some of these lost monuments back to life—sometimes with great success. Perhaps the most famous was the 13th century cathedral at Reims, which burned after a German bombardment in September 1914. The former coronation church of France’s kings, it was the equal of Notre-Dame in beauty; indeed, the two buildings were restored in the 19th century by the same architect, Eugène-Emmanuel Viollet-le-Duc.
The Reims Cathedral caught fire after shells hit some scaffolding on its external walls. Filled with hay bales to function as a makeshift hospital, the church went up like tinder, causing the lead roof to melt and bubble, leaving only scarred walls left. The sense of shock—Marcel Proust and the philosopher Henri Bergson were among the many to register their disgust—rippled across France, with the church being talked of as a “martyr cathedral.”
“There are these very famous pictures of the roof [of the Reims Cathedral] gone, but you can still see the vaults,” Reilly says. “The roof had burned off. Some of the vaults are damaged, some aren’t.”
Restoring what had become a gutted skeleton might have seemed impossible, but the building was pieced back together between 1919 and 1938. What ultimately emerged was a singularly sensitive recreation of the building as it had appeared before the fire, though its wooden roof supports have been replaced with (elegant) concrete. Today, Reims is still a heart-liftingly beautiful place that, in matching muscularity with delicacy and grace, leaves the viewer awed at the things humans are capable of.
It may be days or weeks before French authorities know the full extent of the damage to Notre-Dame, and the cause of the blaze has not yet been determined. The restoration work underway at the cathedral (which was long overdue) has already been fingered as a likely culprit, since this work is hazardous. Restorers use torches in soldering work, for example, and solvents that might be flammable.
“It could just be a tragic accident on a worksite. We just don’t know that yet,” says Peg Breen, president of the New York Landmarks Conservancy. “It has nothing to do with [the building] being old.”
Even determining the scope of the fire will take a lot of work. Now that the fire is extinguished, engineers will need to stabilize the surviving structure before a thorough examination can proceed. Colleen Heemeyer, the manager for grants and technical services at Sacred Sites, a division of the New York Landmarks Conservancy, expects that preservationists will use drones to inspect the damage. Notre-Dame, which drew about 13 million visitors every year, is likely to represent a colossal historic preservation project.
“They’ll have the best and the brightest looking at this structure ASAP,” Heemeyer says. “As far as completing an assessment and designing a plan for stabilization and restoration? I think you’re looking at months, if not years.”
While the damage is sure to be extensive, governments and institutions around the world will be standing by to help, Breen says. “This is a tragedy for the world.”
There was more hopeful news on the day: Paris Match reported that the artworks and holy sacraments of Notre-Dame were all rescued safely. The cathedral’s famous trio of rose windows and original medieval-era Great Organ are undamaged. Reports of injuries were limited to two police officers and one firefighter, according to officials. But the world may have lost some of its most beautiful stained glass artworks, and it could be some time before Notre-Dame’s bells ring out over the city again.