Eiffel Tower Maintenance

The Eiffel Tower is built of riveted (2.5 million rivets!) wrought iron, a material that will last virtually forever if it is painted regularly. Since it was built (for the International Exhibition of Paris in 1889), the tower has been painted once every seven years. Maintenance on the tower includes applying 50 metric tons of three graded tones of paint every 7 years to protect the 200,000 square meters of iron lattice work from rust. The darkest paint is used at the bottom and the lightest shade at the top. Each repainting, by 25 painters working for 15 months, requires 1500 brushes, 5000 sanding disks and 1500 sets of work clothes. On occasion, the color of the paint is changed. The tower is currently painted to a shade of brown. (reference)

Correction by Jock Dempsey of anvilfire.com

The application of an anticorrosion treatment lasts one year, so that the tower can stay open and continue to greet visitors. This legendary structure comprises 220 000 m2 of surfaces that have to be maintained and repainted (7 300 tons of structural metal, and 18 000 metal parts held together by 2 500 000 rivets). Some of these surfaces are very difficult to reach. The budget for the job cost a total of 20 million francs.

The 17th time the Eiffel Tower was to be repainted, there were three new requirements:

The monument had to be cleaned completely, with better preparation of the corroded areas before they were painted

The work had to be inspected

Greater safety precautions had to be taken on the site

The 25 painters who work on the Eiffel Tower still use the traditional methods from the time when Gustave Eiffel designed it. The paint must be applied only manually, with brushes; rollers and paint guns are not allowed.

Special paint systems used

The paints applied to the Eiffel Tower are formulated for this specific purpose. For this 17th paint job, a paint using new, lead-free pigments was developed, tested on 200 m2 of surface, and subjected to reactivity tests by the SNTE (Société nationale de la Tour Eiffel). To emphasize the shape of the tower as seen from the ground, it was painted in three shades of brown specified by the SNTE's architect -the lightest shade at the top, and the darkest at the bottom.

Preparation of corroded areas and complete cleaning of tower

All corroded areas were stripped, sanded, and ground, then received two coats of an oleoglycerophthalic primer containing lead silicate-chromate pigment, which affords excellent resistance to corrosion while maintaining flexibility for the paints applied on top of it. (The areas that were determined not to be corroded were cleaned with high-pressure steam.) The general finishing coat was applied with an oleoglycerophthalic paint containing basic lead silicate-chromate pigment. The colors were Eiffel Tower brown numbers 1, 2, and 3 (one for each level of the tower). This paint has the following properties: highly aesthetic appearance; perfect compatibility with the existing, older paints; excellent corrosion resistance; and complete suitability for the Eiffel Tower.

In total, 60 tons of paint (including 10 tons of primer) were applied in the course of this job. It was estimated that about 15 tons of paint had eroded since the last time the tower was painted.

Galvanizing the Eiffel Tower?

Amazed at the cost and complexity of the work involved in repainting the tower, where the painters must use hooks, ropes, safety nets and cannot begin painting each day until the morning dew has evaporated, a Dutch corrosion expert recently made a hypothetical calculation of cost savings had the Eiffel Tower been galvanized. He made a cost analysis comparing the application of a paint system with a so-called duplex system, whereby the steel is first galvanized with zinc and then painted. With a duplex system, any damage to the paint coating does not lead to corrosion as the steel continues to be protected by the zinc which underlies the paint. (reference)

Had the steel used to build the Eiffel Tower been galvanized before painting, only seven large-scale maintenance operations would have been required, compared to the 17 that have taken place since 1889. The first large-scale maintenance of a duplex system normally takes place after about 25 years (surface preparation and application of a primer and top coats). After this, small-scale maintenance (top coat) and large-scale maintenance take place alternately, after five or seven years respectively.

What does all this mean in terms of cost? Based on today's wage and price levels, and allowing for a favorable purchase price of the large quantity of paint needed, galvanizing before painting - the duplex system - would have saved at least $10 million in maintenance costs! Using modern day prices to calculate construction and erection costs, these savings amount to over 50% of the construction cost.