angle-left The Eiffel Tower sheds its skin
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The Eiffel Tower sheds its skin

The new layer of paint could bring the original red colour back to the Eiffel Tower. Credit: Joe deSousa

Francesco Rodella | Tungsteno

 

The most-visited paid monument in the world is preparing for the most complex painting campaign in its history, a delicate ritual that has been carried out 19 times since Gustave Eiffel delivered the work in 1889. The civil engineer himself warned: “We will most likely never realize the full importance of painting in the conservation of metal works and the more meticulous the paint job, the longer the Tower shall endure.” Since then, the Eiffel Tower has received this special care for its skin, with one complete coat of paint every seven years on average.

With 2019 marking the 130th anniversary of its inauguration, Paris is preparing a further renovation of its appearance, although this time with several added difficulties: the previously superimposed layers of paint make the weight of the structure excessive, impede the strong adherence of a new layer and also contain a very polluting element: lead. The Eiffel Tower Exploitation Society (SETE for its French acronym), the public society responsible for its management, once again faces the challenge of keeping the monument open to the public while carrying out repainting works, but complicated by the commitment to first remove the previous layers of paint from 10% of the tower’s surface. In total these paint layers have reached three millimetres in thickness and 350 tons in weight.

Gustave Eiffel knew to construct his monument from a long-lasting material: puddled iron (wrought iron), but there is still a dangerous enemy always lurking in the background: corrosion. "Painting protects against the effects of air, water and other elements such as pollution and bird droppings," explains the architect Bertrand Lemoine, an expert on the history of the Eiffel Tower.

 

A complex ritual every seven years

For this reason, at least once every decade, an area of ​​up to 2.5 million square metres of iron has to be repainted in an operation that, according to the SETE, even under normal circumstances requires "a rigorous methodology":

- First, the workers search for the most corroded areas (up to 5% of the total area of ​​the structure).

- Next, these points are sanded and two layers of antioxidant primer are applied.

- The less damaged parts are also steam cleaned.

- The paint, whose total weight reaches 60 tons, is applied to the whole structure once these previous phases have been completed.

 

The painting work of the Eiffel Tower is done exclusively by hand. Credit: Alessandro Prada

 

There are some factors (including cold and humidity) that complicate the operation, during which time the state of the structure is carefully checked and, occasionally, parts that exhibit signs of deterioration are repaired. Constant monitoring is needed by experts in anti-corrosion paint who "are responsible for controlling the quality of work done."

Initially, the start of the maintenance works was scheduled for the autumn of 2018 and its estimated duration was three years (twice the normal). But the complexity of the operation has led to a change in plans: the entity responsible for the tower confirms that the painting work has not yet begun and that it is not expected to start before the autumn of 2019. According to SETE: "Things have evolved and the campaign has been delayed."

Lemoine believes that the delay is probably due to the need to perform different tests before being able to carry out the elimination of a portion of the superimposed coats. "Removing paint containing lead requires that the entire surrounding area be protected," he says. "At some points, chemical substances may also be necessary to eliminate the old layers," the architect adds.

 

 

 

In the last two decades, the selection of the materials used has been made more and more meticulously. For the 2002 campaign, those in charge of the monument changed the type of paint that had previously been used because it contained lead pigments, a contaminating material that was harmful to health. After that year, that element was replaced by zinc phosphate, which guaranteed more resistance to corrosion and less contamination. In the next maintenance campaign (in 2009, the last to date), the use of other lead-free paints was experimented with in order to achieve even greater respect for the environment.

 

The objective is that the repainting works do not interfere in the visits. Credit: Chris Karidis

 

This complex renovation also affects other architectural symbols such as the Golden Gate Bridge of San Francisco. "Some say that the bridge is painted every seven years, others that it’s done every year, from end to end. The truth is that the bridge is painted continuously," say those in charge. The tasks of skin care are part of the day-to-day life of both the Golden Gate Bridge and the Eiffel Tower. However, these operations have never interrupted the access of tourists to the Parisian icon. In 2017, its managers said that their intention was to keep the tower open to the public throughout the next painting campaign, in a year as special as the 130th birthday. For the time being we have to wait, since the SETE has confirmed that in the coming months it will communicate new details about the start date of this latest maintenance project.


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Tungsteno,  a journalism laboratory for investigating the essence of innovation, devised by Materia Publicaciones Cientificas for the Sacyr blog

 

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