Schlüter-DITRA
When it comes to waterproofing, uncoupling, vapour pressure equalisation, load transfer, heat distribution: the DITRA mat is unparalleled under tiles.
The Eiffel Tower: Uncoupling a Monument
Category: Historic monument | Location: Paris, France |
Focus: DITRA, DILEX-KS
An exceptional project on an exceptional landmark
Few landmarks in the world are as renowned as the Eiffel Tower in Paris. The 1083-ft structure was inaugurated at the World Fair in 1889 to commemorate the 100th anniversary of the French Revolution. Since the 1980s, the “Iron Lady” has been restored and rebuilt regularly to enhance the visitor experience. However, due to the unique properties of the building, and the ~20,000 daily visitors, such work is no easy undertaking. The renovations of the first level of the Eiffel Tower proved to be both an extensive and exceptional project, with work taking place over an area of 4,586 m2, including the Eiffel and Ferrié pavilions, three access structures to the elevators, as well as the façade of the restaurant.
The main challenge: a structure in motion
As part of this unique construction project, installation company EDM Paris was commissioned to install a natural stone floor in the Ferrié Pavilion. In addition to nearly 300 m2 of floor tile, approximately 85 m2 of wall tile was installed in sloped areas, as well as a staircase, and various structural pieces, including benches and counters. The sheer volume of tourists and the resulting vibrations represented a special challenge. “It made a standardized, conventional approach impossible,” explains Sebastien Sollier, project manager at EDM Paris. “We had to obtain a structural engineering report to have the material and the method for implementing the work approved. Above all, we had to take the enormous weight load into consideration.”
Every single element that was removed from the pavilion was brought down and weighed, and the same procedure was followed for every element that was transported up. We were working under the requirement that the weight of the Eiffel Tower had to be exactly the same after the renovation as before.
At the request of the architect, the bulk of the floor area was to be covered with natural stone panels in a size of 100×100 cm. In order to limit the weight of these panels and to avoid an assembly height exceeding 10 mm, EDM recommended the use of the Stone Performance technology. Stone Performance is a specialized company that offers natural stone products for a wide range of requirements. The panel chosen in this case is a material mix consisting of a 10-mm natural stone layer on fiberglass, which is structurally bonded across the entire surface. The material is highly resistant to bending, compression, and puncture. EDM had used it in the past floor coverings in elevators and other areas with high traffic volumes.
The material was installed over a steel substrate panel in the Ferrié Pavilion. After applying a bonding primer, the EDM workers began to install the uncoupling membrane Schlüter-DITRA 25 (now DITRA). It not only serves to neutralize different tensions between the covering and the substrate, but also absorbs the building’s vibrations, as Sébastien Sollier emphasized: “When we were calibrating our laser leveling device, the display kept moving back and forth. The tower is constantly in motion, which is particularly noticeable at peak visitor hours. The level only was reasonably stable in the morning, when the tower was still closed for visitors.”
The bonded uncoupling membrane was installed with a flexible, malleable adhesive mortar by Mapei, which allowed for the installation of the panels after a curing phase of the mortar. The bonded assembly of natural stone and fiberglass was attached to the mat with an epoxy-resin modified two-component polyurethane adhesive. The Stone Performance panels, which weighed approximately 25 kg each, were set into place with suction lifters. The entire covering area was subdivided into 40 m² segments, using movement profiles of the type Schlüter-DILEX-KS. These profiles, which were also installed in the door transition areas, are optimally suited to absorb the continuous movement and elongation changes caused by sunlight within the covering.
The installation occurred in sections of approximately 20 m² at a time: One team was busy installing the uncoupling membrane, while another team started installing the floor covering after curing.
Perfectly orchestrated
Overall, this extraordinary renovation project required strict organization to stay within the tight time schedule. Ten workers were involved in the on-site installation for approximately three months, while the preparation of the construction work took half a year. According to Sollier, the working conditions were anything but ordinary: “We had no storage space on site, and all materials were stored in a Paris suburb. Deliveries could only be made between 7 and 9 am in the morning, while the tower was still closed. The material was stored in a transit zone at the base of the tower and transported up after weighing with a lift platform. This platform only went up once a day before the tourists arrived. That meant our material supply had to be perfectly timed and nothing could be forgotten.”
As soon as the lifting platform with a carrying capacity of 9 metric tons had reached the first level at a height of 57 m, it became part of the construction site situated between two balconies and served as a temporary storage space. In the evening, the construction waste was moved down and weighed to stay within the balance of the weight load as discussed above. The entire, complex renovation of the first level took approximately two years to complete. The reliable bonded uncoupling assembly now guarantees the permanently damage-free appearance of the attractive floor covering, even under these extenuating circumstances.
