PlanGrid Construction Productivity Blog

From St Paul’s to Notre-Dame: How Technology Is Changing Reconstruction

On 15th April 2019, the world watched in horror as flames engulfed the Notre-Dame Cathedral in Paris. It took just hours for the iconic spire and wooden roof to collapse, changing the face of a building that has shaped the Paris skyline – and French culture – since 1345.

The fire at Notre-Dame was devastating, not only to the French and Roman Catholic communities but to people around the world. The unmistakable Gothic architecture has made the World Heritage site one of the most recognisable and beloved buildings in history.

With a bittersweet nod, the two famous stone towers and most of the structure survived, and attention quickly shifted to restoring the site. President Macron has even set the highly ambitious target of completing repairs by the Paris Olympics in 2024, a mere five years away.

Throughout history, communities have had to contend with similar challenges, as architects struggled to repair or rebuild national icons. But Notre-Dame is a symbol of how technology is opening up new possibilities to restore and save ancient icons for future generations.

“Thus lay in ashes that most venerable Church”

St Paul’s Cathedral in London is most commonly associated with endurance. The church’s almost miraculous survival during the London Blitz bombing in 1940-41 was seen as a symbol of good fortune and hope for the country. But in fact, the church’s iconic structure was created in the wake of the traumatic destruction of its predecessor, during the Great Fire of London in 1666.

Old St Paul’s had lived through some difficult days following its construction in 1087. During the Civil War just thirty years before the Great Fire, the building had been dilapidated when extreme Protestants used the naves as stables. In the 1660s, architect Christopher Wren had already been commissioned to restore St Paul’s to its former glory.

But before Wren’s work commenced, the Great Fire began. A witness John Evelyn wrote, “The stones of Paules flew like granados, ye melting lead running down the streets in a streame. Thus lay in ashes that most venerable Church, one of the most antient pieces of early piety in the Christian world.”

Temporary repairs were undertaken, but Wren declared that it was impossible to restore the ancient building. Even taking down the ancient structure stretched the construction techniques of the day; the molten lead had fused much of the stonework together. Wren ordered the novel step of using gunpowder to destroy the walls, to make way for his white-domed masterpiece.

Unfortunately, today we’re only left with medieval floorplans and early modern sketches of Old St Paul’s, the church that had watched over London since the Norman Conquest.

A Gothic masterpiece

Reconstruction techniques and records improved considerably over the centuries following the Great Fire of London – and one building to benefit was Rouen’s Notre Dame Cathedral, considered to be the tallest cathedral in France.

This impressive structure, captured in paintings by Monet more than 30 times in varying light and weather, held the title of the tallest building in the world from 1876 to 1880, until it was surpassed by the Cologne Cathedral. Throughout the years, Rouen Cathedral experienced hardships including a fire in 1200, damage by the Calvinists during the French Wars of Religion in the 16th century, and bombings during the Second World War. During World War Two, Rouen was attacked by the RAF as part of the Allies’ efforts to retake France, which levelled almost 45% of the city. Seven bombs hit the cathedral, damaging the south side and destroying two rose windows. A second bomb by the US Army Air Force burnt the Saint-Romain Tower, the oldest in the building, leaving two molten puddles where the ancient bells had melted. The people of Rouen embarked on an ambitious rebuilding project to restore their cathedral to its former glory. Luckily, the damage was not as extensive as it could have been. In 1939, almost all of the stained glass windows in Rouen had been removed; today, it’s still possible to see windows in the cathedral from as early as 1210.

 The urgent repairs were successful, preventing the spire from crashing down onto the building and paving the way for the reconstruction project. And thanks to more modern tools and techniques, the building was repaired and reopened just twelve years later in 1956 – and still forms a focal point for the city.

A digital Notre-Dame

A key issue for the repair and restoration of ancient buildings has been a lack of documentation about how those buildings were actually constructed. Medieval architects were often highly experimental with their structures; unfortunately, it wasn’t uncommon for walls and roofs to collapse.

But technology is available today that can both map and support repairs on buildings created thousands of years ago. Building Information Modelling (BIM) software has been used for many years to create building designs. Now the technology will enable Notre-Dame’s repair teams to create a digital model to guide work on the building.

Autodesk is using the scans taken by specialist consultants Art Graphique & Patrimoine before the fire to develop a comprehensive digital model of Notre-Dame, to guide reconstruction. Mobile technology means it’s even possible to bring this information to the site; 2D and 3D BIM models can be accessed on smartphones and tablets with PlanGrid, to directly guide repairs.

Modern technology will play a pivotal role in undoing the critical damage to Notre-Dame – and help repair teams to meet the ambitious deadline of the Paris Olympics in 2024

Creating a virtual history

The destruction of historical buildings is a highly emotive and distressing event. In the past, the loss of a building was often accepted as a tragic part of everyday life, but the apparently accidental damage to Notre-Dame seems even more poignant and unthinkable in modern times.

Fortunately, today new technology should help to complete comprehensive repairs to Notre-Dame, restoring the building to its former glory. And new digital records can help to ensure that, come what may, future generations can experience this vital link to the past.

Read how the restoration of Notre-Dame mirrors the creation of another international icon, the Sydney Opera House.

Amanda Fennell

Amanda Fennell joined PlanGrid in October 2017. As Head of Marketing in EMEA, based in the UK. She has 20 year's marketing experience in IT, including working with some leading cloud organizations. She was the first marketing recruit in EMEA and supported the launch of the company in the region. Amanda holds an MA in Communications and Cultural Studies from DCU, Ireland.

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