Notre Dame Roof Rebuild Utilizing Medieval Techniques

FRIDAY, JUNE 9, 2023

According to recent reports, the roof of the Notre Dame Cathedral is being rebuilt using medieval woodworking techniques. The reconstruction reportedly hit a milestone last month when large parts of the new timber frame were assembled and erected at a workshop in western France.

The news arrives as French officials announced earlier this year plans to reopen the historic structure at the end of 2024, less than six years after the building caught fire in which its iconic spire and nearly two-thirds of the roof were destroyed.

Roof Background, Rebuilding Efforts

Before the fire, the wooden lattice structure underneath the cathedral's lead roof was known as the “forest.” It was made up of old oak trees that were added to the cathedral between 1220 and 1240. 

Its dimensions reportedly measured more than 300 feet long, 42 feet wide and the transept was over 30 feet tall. Before it collapsed in the fire, it was considered one of the oldest frameworks in Paris.

As part of the reconstruction efforts, workers will reportedly install 26 timber frames, known as “bents” or “trusses.” According to the Friends of Notre-Dame de Paris, in March 2020, 1,000 oak trees were cut from roughly 200 French forests to make the frame for Notre-Dame Cathedral’s roof and spire.

These trees were reportedly selected through a “painstaking process” in January and February 2020 to fit the precise requirements defined by the chief architects in charge of restoration. The oak trees are roughly 150 to 200 years old, with some standing over 60 feet tall.

The wood was then dried for 12 to 18 months to make sure it does not shrink or move once in place.

The Associated Press reports that crews worked with hand axes to fashion the beams for the framework, just like their predecessors’ work back in the 13th century.

“It’s a little mind-bending sometimes,” said Peter Henrikson, one of the carpenters. He says there are times when he’s whacking mallet on chisel that he finds himself thinking about medieval counterparts who were cutting “basically the same joint 900 years ago.”

The goal of hand tool use for the rebuild is to pay tribute to the craftsmanship of the cathedral’s original buildings, as well as ensure that the “centuries-old art of hand-fashioning wood lives on.”

“We want to restore this cathedral as it was built in the Middle Ages,” said Jean-Louis Georgelin, the retired French army general who is overseeing the reconstruction. “It is a way to be faithful to the (handiwork) of all the people who built all the extraordinary monuments in France.”

Additionally, carpenters and architects are reportedly using computer design and other technology to speed up construction. Computers were used in the drawing of plans to help ensure that their hand-chiseled beams fit together perfectly.

“Traditional carpenters had a lot of that in their head,” Henrikson noted. It’s “pretty amazing to think about how they did this with what they had, the tools and technology that they had at the time.”

In May, crews assembled and erected large parts of the new timber frame at a workshop in the Loire Valley, France. The “dry run” reportedly assured architects that the frame is fit for purpose and the next time it is anticipated to be put together will be on top of the cathedral. 

“The objective we had was to restore to its original condition the wooden frame structure that disappeared during the fire of April 15, 2019,” said architect Remi Fromont, who did detailed drawings of the original frame in 2012.

The rebuilt frame “is the same wooden frame structure of the 13th century,” he says. “We have exactly the same material: oak. We have the same tools, with the same axes that were used, exactly the same tools. We have the same know-how. And soon, it will return to its same place.”

Fire Background

On the evening of April 15, 2019, flames engulfed the more than 850-year-old Notre Dame Cathedral, destroying the spire and nearly two-thirds of the roof. There were no initial reports about what had caused the blaze, though police said at the time that it appeared to be accidental and that the cause could be linked to the ongoing 6-million-euro ($6.8 million) renovations. Since then, though, investigators have said that they believe an electrical short-circuit was the culprit.

While restoration work was delayed due to the COVID-19 pandemic, work officially resumed at the site in May 2020. The following month, the scaffolding dismantling process restarted. By September 2021, the French government agency overseeing the reconstruction of France’s Notre Dame Cathedral reported that efforts to secure the structure had reached competition.

Possible design changes for the cathedral’s spire were already being discussed just days after the fire, and French Prime Minister Edouard Philippe even launched a spire design competition, saying that instead of recreating the original spire, the city hoped to create a new design that is “adapted to the techniques and the challenges of our era.”

Since the spire was not a part of the original structure, or even the first spire built for the cathedral—the first spire was believed to be built between 13th and 18th centuries, and was removed due to wind damage; the second spire was added during the 19th century restoration by French architect Eugène Viollet-le-Duc—questions about replicating the tower arose.

Since then, several ideas were revealed, including: Italian architects Massimiliano and Doriana Fuksas proposed a contemporary roof and spire made from Baccarat crystals that would be lit up every evening; French designer Mathieu Lehanneur proposed a golden, fire-like structure; Bratislava-based Vizumatelier proposed a lightweight tower that would shine a beam of light directly upward; Cyprus collaborative architectural studio Kiss The Architect suggested various arches and balls wrapped around a central staircase-type spire; and Paris-based architects Studio NAB submitted a design proposing a greenhouse and educational apiary to sit upon the damaged landmark.

However, about a month after the fire, the French Senate passed a bill that would require the cathedral to be rebuilt to its “last known visual state,” a move that pushed back against the proposed innovation for the structure.

In May the following year, building software firm Autodesk confirmed in a press release that it will be helping Notre Dame Cathedral officials by contributing design and construction solutions to the rebuilding efforts, including BIM support and technical expertise.

However, in December 2021, proposed changes announced regarding the restorations reportedly outraged critics, relating the designs to world-renowned Walt Disney Parks to create a more tourist-friendly makeover. However, more damaged elements are still set to be restored to their former state.

According to church officials, the proposed revamp and new designs would serve to better explain Christianity to the landmark’s millions of annual visitors in a more accessible format. The renovation is slated to replace confessional boxes, altars and classical sculptures with modern art murals, new lighting and sound effects.

The combination of art, light and sound are designed to create what the church calls “emotional spaces.” In addition, the restoration plans also call for the creation of “discovery trails” through themed chapels. Throughout these “trails,” various Bible scriptures would be projected onto the walls in various languages.


Tagged categories: Architects; Architecture; Color + Design; Commercial / Architectural; Design; Design - Commercial; EMEA (Europe, Middle East and Africa); EU; Historic Preservation; Historic Structures; Maintenance + Renovation; Ongoing projects; Program/Project Management; Projects - Commercial; Restoration; Restoration; timber; Wood

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