Problem

The Lakanal work site posed a twofold problem: the exterior restoration of a building classified as a historical monument in an occupied site.

The main difficulty posed by this very large-scale project was the size of the structures to be erected. 37,500 m² of scaffolding, weighing 240 metric tons, on an occupied site, usable only during school holidays.

• the restoration of rooftop items (chimneys, ventilation towers, lightning rods);
• the restoration of the rooftop;
• the renovation of façades (stone and brick);
• the replacement of external joinery (windows and doors);
• the renovation of the chimney culminating at 33m and still in operation.

Solution

While the solution did not pose any specific architectural difficulties, it called for the organising of the managing of the volume and the technical choices required for very fast, reliable erection.

The whole project was based on a complex structure using free-standing scaffolding and suspended scaffolding with cantilevered doors on certain levels and primarily on the rooftops.

The true "CHALLENGE" was to bring together a team of 30 fitters on a project that was unique in size. The planned total length of this project, divided into several phases, was 3 years. The work site was divided into 3 phases, with 1 phase per year. Scaffoldings were erected around buildings 3 parts, each of 10 to 15,000m².

The technical solution to the problems posed by this site mainly involved the use of two flagship products from the Tubesca Comabi scaffolding range: M368 and R200.

In addition to this, Tubesca-Comabi has developed specific parts, known as a "double offset". These advances fill the gap between the scaffolding and the façade to allow the carpenter to enter the window openings to carry out the work.

To carry out the work on the chimney, involving replacing the stone, repointing the bricks, installing a lightning rod and including a new crinoline, the technical and environmental requirements for the installation of this chimney precluded the installing of support points on the rooftop. The construction of a self-stable scaffolding for the renovation of the chimney was therefore inevitable.

The time taken to erect scaffolding around the chimney was 3 weeks with 4 specialised fitters for a total estimated work time of 2.5 months. In all, 35 metric tons of scaffoldings will have been used to build the structure around the chimney.