This renowned edifice has 220 000 m2 of surfaces that must be maintained and repainted on a regular basis (7 300 tons of structural metal and 18 000 metal parts held together by 2 500 000 rivets). Some of these surfaces are quite difficult to access. The job cost a total of 20 million francs in budget. Actually, the tower costs more to maintain than it does to build. Its construction began in 1889 for 100 million francs (at the time, this was a huge amount of money) and is still not finished. The original plan was to finish it in five years at a cost of 250 million more francs, but this deadline was never met. The main problem is that the tower is made of iron and iron rusts. To prevent this from happening, the site it's built on is covered in gravel and clay so the ground around it isn't able to reach the temperature required for steel to melt or boil. The tower is also wrapped in foil to protect it from ultraviolet radiation and painted with non-toxic materials. The paint job needs to be done about every ten years because old paint falls off under its own weight. The keepers work between one and three hours a day depending on the season, taking care of small tasks such as washing the windows or sweeping the floor. They use hand tools because they don't have enough power for heavy machinery. The annual maintenance budget is about $1.5 million.