MASTERPIECE OF ARCHITECT VAUBAN CLEANED
As part of its cultural sponsorship, Kärcher cleaned the main façade of the Citadel of Besançon.
With its extensive fortifications, the Citadel of Besançon is one of the finest masterpieces of the famous architect Vauban. Built between 1668 and 1683, it boasts an eventful history as a fortress, prison, storage area and currently place of interest with a zoo and several museums. Within the framework of its cultural sponsorship, the family-run company Kärcher cleaned the facade of the main entrance to the citadel facing the old town of Besançon as well as the entrance portal free of charge.
The over 120 metre long and up to 14 metre high so-called "Front Saint-Etienne" is made of beige-coloured limestone blocks, which were removed on site and set down directly on a boulder. The Kärcher experts abseiled down the coping in order to clean the facade. The gentle steam stage of a hot water pressure washer was chosen as a cleaning procedure.
"It is important that we work with a low impact pressure of only 0.5 to 1 bar and mainly with water steam", explains Nick Heyden, who was responsible for the project on site. "The dirt is mainly loosened by the high temperature of the steam, which is about 95 degrees Celsius on the stone surface. Water pressure is basically not available with this method. This type of cleaning is very gentle and does not damage the original material of the wall."
Another advantage of cleaning with hot steam is that the seeds and spores in the rock pores are killed off by the high temperature, which will delay any regrowth. As the availability of power and water is sometimes difficult to guarantee directly at the wall, in addition to classic hot water pressure washers, the Kärcher team also works with a hot water high-pressure trailer, which can be used as a standalone unit without a power and water connection in the building. At the entrance portal the Kärcher experts also use the so-called low-pressure microparticle blasting on some areas in order to remove black crusts.
The Citadel of Besançon towers over the capital of the Franche-Comté region and is the central element of the fortifications built by Vauban in Besançon. The citadel is a striking example of military architecture and has been listed as a UNESCO World Heritage Site since 2008. It is considered one of the finest citadels in France and is one of the key tourist and cultural attractions in eastern France. Over 280,000 people wander through the fortress walls every year to marvel at the city and surrounding nature, to visit the three French museums, including the zoo, and to take part in dozens of performances and events taking place in the heart of the fortress.
All facts at a glance
Country: France
Place: Besançon
Kind of dirt: Biological growth: moss, algae, bacteria, black crusts, limescale deposits
Cleaning technology: Steam stage of the hot water high-pressure cleaner, low-pressure micro-particle blasting
Exeution: March 2024
