For decades, smoke billowed from the chimneys of Belval in the north-east of Esch-sur-Alzette. These are now times gone by. The manufacture of raw iron in Luxembourg ceased in 1997 when the last blast furnace was decommissioned. The Möllerei, situated at the foot of blast furnace A, is one of the remaining industrial buildings at the Belval site. Built in 1912, the majority of the structure is listed. The top priority of the renovation and conversion was therefore to preserve the building as it was in 1970.

It was with this in mind that the corroded metal cladding of the façade was replaced with new sheet metal panels and the roof was also updated. However, a deliberate decision was made not to upgrade the thermal insulation to today's energy efficiency standards: “The decision was made at the time that we would protect the building against external weather influences, but that indoor temperatures between 12 and 15 degrees would be sufficient for the use of the events and exhibition space,” explains Julia Nockemann from architectural practice BFF architecture & urbanisme, who were responsible for the project. “The client also wanted to retain the look of the ribbon windows as far as possible.”

As the heritage preservation authorities valued the preservation of the external appearance more highly than the energy-efficient refurbishment, the ribbon windows of the two long façades and the gable façade were ultimately renovated using the non-insulated Jansen Economy 50 steel profile system. In keeping with the industrial character of the building, the heating system was also reduced to a minimum. This does not, however, rule out the hosting of events in winter, as the areas designated for events have all been constructed using thermally insulated profiles. Included in this in particular is the new entrance area with its adjacent foyer. Here, the thermally insulated Jansen VISS Façade mullion/transom façade system was used, which enables especially elegant façades to be created. The entrance doors themselves were fabricated from the Janisol steel system, which is also thermally insulated.