On the April 15, 2019 when the most visited monument in Paris, Notre Dame de Paris caught fire, passers-by could not believe their eyes and people around the globe were shocked as they watched the central spire collapsed. Fortunately, despite the massive fire which engulfed the entire roof structure and the spire, the cathedral was saved from major collapse. The major credit for saving Notre Dame de Paris from even greater disaster goes to the firefighting team that arrived on the site soon after the alarm was set off.
Smoke was seen rising from the roof of the Notre Dame cathedral in Paris and at 6:18 pm the alarm was immediately raised. Though fitted with the most highly sophisticated alarm a system with smoke detectors, there was initial confusion about where the fire was located. At 6:45 pm the alarm was raised again while the fire had already spread over the wooden roof structure and by 7:00 pm over six hundred firefighters arrived at the site for the rescue mission. However, within an hour of their arrival at 8:00 pm the spire collapsed and the fire engulfed the entire roof structure. If only the location of the fire would have been immediately located after the first alarm, the famous spire of Violet-le-Duc might have been saved.
Response to the Notre Dame fire in Paris
Once the fire was located the response was carried out in a highly professional manner. The firefighters drew sketches planning out the strategy to approach this situation, clearly reflecting their level of training and knowledge of the historic structure. Water was pumped from the Seine to spray on the inferno while important artifacts were removed from the monument including the most precious relic, the Holy Crown of Thorns. An emergency evacuation was carried out successfully as per preparatory planning.
The roof structure built of timber covered thin stone vaults of the main cross-shaped structure of the cathedral, the naïve and the transept. The timber dried over centuries quickly caught fire. The lead roof melted and possibly further fuelled the flames. The large sections of wood were later found to be charred only on the surface, which meant that the smaller timber elements were the main fuel for the fire. At 7:37 pm the roof collapsed, beginning with the eastern naive. The spire which is largely timber structure caught fire in a spectacular manner and collapsed at around 8:00 pm. A restoration the project had just started on the spire and huge steel scaffoldings had been erected which remained in place but were deformed and welded together by the heat.
The fire raged on, threatening the towers and the belfry. Though the fire spread to the northern tower, it was lucky that the timber beam on which the bells hung survived. By this time at several locations, the timber elements from the roof and spire had crashed through the stone vaults into the cathedral. The firefighters got the fire under control by 10:30 pm and the fire was put out by 2:00 am. The clearing and initial assessment of the monument were done by robotic vehicles which included the removal of timber, stone, and remains of the melted lead. Rather surprisingly, and thanks to the extraordinary competence of the firefighters, the stained glass windows and many artifacts along the side aisle of the cathedral and the main towers and belfry were saved. A team of conservators was involved in salvaging important artifacts, however; the eight allegories on the spires had already been removed for restoration just a few days before the fire. One of the objects also found within the debris that fell into the cathedral was the finale of the spire, the cock.
While the firefighters were struggling to save the monument from any possible major disaster, major companies and enterprises from around the world started pledging donations for its restoration. Within a few hours there were pledges of hundreds of millions of Euros from the owners of major luxury brands such as Gucci, Yves Saint Laurent and Louis Vuitton, as well as the French oil company Total and even Disneyland.
Preparing Notre Dame de Paris for research and restoration
A major restoration of the northern main façade of the Notre Dame was done in the 1990s. However, the state of conservation of the Notre Dame de Paris before the fire was appalling with most of the decorative stone elements including the gargoyle and stone balustrade being very fragile. The stone masonry of the flying buttresses was unstable while the spire was tied in place using a metal belt. Therefore a major restoration project was approved as per the report presented by the conservation architect in 2013.In 2018 work began on restoring the spire and one of the flying buttress on the southern side. The first task of this project was the restoration of the spire. The spire over the central transept designed by Viollet-le-Duc, inspired by the spire of the nearby Sainte- Chapelle, was added during a restoration carried out between 1845 and 1864. An earlier spire was lost at the end of the 18th century and the cathedral was in a desolate condition with interest only being raised by Victor Hugo through his novel published in 1831. For the site preparation huge metal scaffoldings were erected while making sure they don’t rest on the 12th century roof structure named “la forêt” (the forest). Therefore, when the fire engulfed the entire roof structure, the scaffolding did not collapse which otherwise would have cause even greater damage.
On-site cleaning and emergency stabilisation work has been going on since the week following the fire. Visibly the Notre Dame fire destroyed the timber structure of the roof and central spire. Some timber elements fell through the stone vaults and smouldered on inside the cathedral hall. However, the presence of the stone vault prevented the fire getting into the cathedral. Some stone columns inside the cathedral were found to have been damaged by the heat. However, the detail condition assessment of the monument and the impact of the fire on the masonry structure and the stone vault has not been done yet. Considering the safety of the people working on site, temporary stabilisation and site preparation with installation of working platforms will be put in place inside the cathedral before the assessment commence.
The loss of the roof structure and possible damage of the stone vaults that span the main naïve could impact the overall structural stability. The flying buttresses provide the tall stone columns lateral support, and with the removal of the link at the top, this could put pressure on these columns which might already be weakened due to the fire. As a precautionary measure, timber framing have been inserted inside the flying buttresses to counteract the lateral forces. The gable walls of the roof structure which are freestanding now after the loss of the roof structure have been provided with the timber support structures to avoid further damage. The stained glass of the upper windows has been removed for protection and the openings covered. The vaulted ceiling has been covered to protect it from rain water though this was not possible where the massive scaffolding the still stands, erected around where the spire once stood. The damaged interior columns have been temporarily tied using steel-cables and timber planks packing. One of the major challenges of the site preparation will be to dismantle the huge metal scaffold which is welded together due to the heat from the fire. Another challenge would be the cleaning of the gargoyle stone from where the melted lead drained out. All the materials that have been collected from the destroyed sections of the monument stored on site in front of the cathedral.
The burning roof structure and the melted lead fell on the stone vaults. The incredible heat that was generated would have affected the stone as well as the lime mortar. Furthermore the water that was used to douse the fire would have washed away some of the mortar. This is possibly one of the most critical points requiring assessment to know if the stone vaulted ceiling could be restored or will require complete dismantling. It would of course be possible to inject mortar in between the stone elements if the stone itself hasn’t been affected too much. For the detail assessment, two working platforms above and below the vaulted ceiling will be installed. Most of the restoration work done on the monument within the last few decades was focused on its architectural features. The damage caused by the fire has necessitated major restoration works and this can be seen as an opportunity to carry out research on the condition of the entire masonry structure from the 12th and 13th century.
Discussion on design and materials for reconstruction
Already within a week of the fire various design options for a new roof structure could be found floating around on the internet . There were also concerns on the unavailability of the required timber for reconstruction of “la foret”. This led to the discussion on the various possibilities of using metal or reinforced cement concrete (RCC)to rebuild the roof structure, solutions which has already been used for various other restoration work on cathedrals in France. The roofing structure was rebuilt using RCC in the cathedral of Reims and Nante while the roof of the cathedral of Chartres was rebuilt in metal. It is considered that the craftsmanship for the rebuilding of the roof structure similar to the 12th century is still available. The traditional craftsmanship has been continued through the apprenticeship with the masters by the Compagnon du Devoir which is a French organisation of craftsmen and artisans dating from the middle age.
The newest issue that has arisen is that of lead pollution caused by the burning lead roofing. This led to a law suit and the site was shut down for almost a month. This will lead to further interesting discussions in regards to what material should be used when restoring the roofing.
During the 19th century restoration carried out in Notre Dame by Viollet-le Duc a new design of the spire was introduced considering that there was no detail documentation of the earlier structure. With the available details of Viollet-le- Duc design as well as the recent 3d scanning of the monument, there is enough documentation to reproduce the roof structure and spire if desired. However, with the announcement of anointer national design competition by the French President this would bring about new concepts for the roof and spire. It will be interesting to see what Notre Dame will look like after the restoration work.