As the last wisps of smoke rose from the charred detritus tumbled in the nave of Notre Dame in Paris, President Emmanuel Macron addressed his nation: “We will rebuild Notre Dame, more beautiful than before,” he said, “and I want it done in the next five years. We can do it.” Anyone with any knowledge of what is involved in the restoration of a historic building, let alone one that has suffered such a catastrophic level of damage, is tempted to respond: “No we can’t.”
Macron’s sonorous words may have been good politics (not least because his five-year plan neatly coincides with the Paris Olympics in 2024) and a sign of the cathedral’s symbolic importance to the country. But those tasked with implementing them won’t thank the president for imposing such an unrealistic timescale – and the expectations that come with it ‒– upon them. Five years is a long time in politics but restoration is a painstaking business that doesn’t correspond to the Élysée cycle. More informed estimates see the rebuilding of Notre Dame as taking anything from ten to 40 years.
This is nevertheless a blink of the eye. There is nothing about Gothic cathedrals that moves quickly. They stand as a testament to faith and hope with their original, usually anonymous, architects and builders trusting to God that what they started, future generations would finish: their originators knew they would never live to see the completed building. Cathedrals are accretions that tended to evolve organically and change both style and shape (as Romanesque turned to Gothic and Gothic itself morphed into numerous varieties) during the course of their construction. Ely cathedral, for example, took three centuries to build (1083-1375); Cologne nearly two and a half (1248-1473) before work stopped, only to be completed to the original plans in 1880. When work started on the Duomo in Florence, in 1296, the designers had no idea how its planned octagonal dome was going to be constructed (building continued regardless and the problem was only solved almost 150 years later by Filippo Brunelleschi, who won a competition to crack the seemingly intractable problem).
The first cathedral since the sixth century to be finished in its architect’s lifetime was Christopher Wren’s St Paul’s. With the notable exception of the new Coventry cathedral, built in just six years after the Gothic original was destroyed by bombs during the Second World War, even 20th-century cathedrals are generational projects. Construction on Antoni Gaudí’s La Sagrada Familia in Barcelona (not technically a cathedral but popularly one) started in 1882 and it remains a work in progress with the builders rushing to finish it by 2026, the centenary of the architect’s death.
Recent examples too suggest that Macron was more presidential than prescient in his diktat. The nearest equivalent to the Notre Dame fire was the conflagration that destroyed the roof of the south transept of York Minster in 1984. Restoration took four years but the damaged area was merely a fraction of that lost at Notre Dame. When a major fire, apparently caused by an overturned candle, broke out in one of Hampton Court Palace’s grace and favour apartments in 1986, the restoration programme took six years. And when a tranche of Windsor Castle suffered the same fate in 1992, it took five years to return the royal residence to its former glory.
All were lesser tasks than those confronting the hard hats currently swarming over Notre Dame. In the days immediately following the fire an international competition was launched to design a new spire and this was itself a sign of the long view needed. One of the questions those in charge of restoration must answer is whether the rebuilding should seek to be a facsimile of what was lost or add a new, modern chapter to the cathedral’s story.
Notre Dame is not itself a coherent building. It was largely constructed between 1163 and 1345, but was added to and modified over successive centuries. During the 17th and early 18th centuries, parts of the interior were classicised and the weather-damaged spire removed in 1786. Many of its statues were destroyed or desecrated during the French Revolution (its 28 statues of biblical kings were mistaken for French kings and beheaded, while a sculpture of the Virgin Mary was replaced with the Goddess of Liberty). Some remedial work was carried out under Napoleon, who was crowned there – or rather crowned himself there – in 1804, but the cathedral remained a partial wreck until the success of Victor Hugo’s Notre-Dame de Paris (known to us as The Hunchback of Notre Dame), published in 1831, reminded Parisians of its importance.
A mid-19th-century restoration under Viollet-le-Duc added the 750-tonne oak and lead spire, a series of 12 copper statues of the apostles – which, fortuitously, were taken down for cleaning days before the fire (11 faced outwards, surveying Paris, with the figure of St Thomas, the patron saint of architecture, facing the spire itself) – and some strikingly sinister gargoyles.
While the conceptual discussions about the modernity or otherwise of the restorations are batted back and forth, the existing structure needs to be stabilised. The roof will have to be covered to minimise weather damage; the debris needs to be sifted by archaeologists both to see what might be salvaged and for clues as to the building’s original construction. The stonework is said to be sound but will require extensive testing: intense heat followed by a dousing in cold water, which is what occurred during the fire, is a recipe for weakening stone. The cathedral was built from Normandy limestone; when strongly heated, limestone decomposes to give off carbon dioxide and calcium oxide, and when water is added, it can turn to powder. In 218 BC, Hannibal’s engineers supposedly used fire and vinegar to split rocks that were barring his route across the Alps.
The stained glass too, one of the glories of the cathedral, survived but may well be suffering from “thermal shock”: the lead beading that separates and holds each piece of coloured glass in place is likely to have sagged in the heat, with both the joints and the whole structure weakened.
Gothic cathedrals were built to be held up by a series of counteracting stresses and calibrated weight transfers (such as Notre Dame’s celebrated flying buttresses). The stone vaulting, now punctured in several places – at least twice in the nave and in the north transept – was meant to be largely self-supporting (each stone held in place by the pressure of those surrounding it) but the holes caused by the falling roof timbers and spire have shattered that structural integrity. Restoring the vaulting may prove a more daunting task than it first appears. There is also the inevitability, familiar to most homeowners, that once outer layers are peeled back a variety of unsuspected structural weaknesses will be found to be lurking beneath.
As for the roof itself, both the spire and the beams, some 13,000 of them, were made of oak sourced in France (the oldest trees, dating back to around 800, were felled between 1160 and 1170). As Bertrand de Feydeau, vice president of the preservation organisation Fondation du Patrimoine, has said: “We no longer have trees on our territory of the size that were cut in the 13th century and were in what we call the primal forest.” He estimated that the original roof used 21 hectares of oak trees – so many that the roof structure was called the “great forest”. Estimates suggest that some 3,000 oak trees are now needed, the most realistic source being the Baltic states.
It is also unlikely that the beamed space between the roof and the vault will be left open as before. During the conflagration it acted as a firebreak separating the roof and the cathedral’s interior, but its openness also allowed the fire to spread the length and breadth of the roof space. After the roof of Strasbourg’s own Notre Dame was destroyed in 1870 during the Franco-Prussian War, it was rebuilt in three sections so that a fire can no longer leap from one part to the other, and a similar solution is likely to be adopted in Paris.
Amid the disaster, though, there was one major piece of good fortune. Common to almost all cathedrals, no original plans exist – but some medieval building accounts detailing measurements and materials do, as do Viollet-le-Duc’s drawings from the mid-19th-century restoration. Best of all is an extraordinary archive of 21st-century data.
In 2011, two American academics, Andrew Tallon and Stephen Murray, launched an open-source project called “Mapping Gothic France”. Part of their work was laser-mapping some of its cathedrals, and Notre Dame was one of them. As they scanned the cathedral’s hidden spaces, as well as its visible ones, the two men compiled a record of millions of data points with measurements accurate to 5mm, so there exists a highly detailed resource that Murray is keen the French authorities should use.
Coincidentally, Ubisoft, the creators of the video game Assassin’s Creed: Unity, in which Notre Dame features large, has donated €500,000 to the restoration, but also offered the data it collected about the building over the course of 14 months when designing the game. That such high-tech resources should be utilised is only appropriate; Gothic was, after all, the cutting-edge style created from the most innovative technology of the time.
For the foreseeable future though, the cathedral’s congregation will consist of structural engineers, architectural historians, stained-glass and stone experts, masons and carpenters, archaeologists, planners and clergy. Macron pointed out in his address that the fire “reminds us that our history never stops and we will always have challenges to overcome”. As his five-year deadline approaches, he might find that the challenges the building throws up are deeply inconvenient, and that he has merely swapped trouble with the gilets jaunes for problems with a different set of high-vis wearers.