Iron Castle of Ath, BELGIUM
Built in 1887 in the city of Ath, the Iron Castle (Château de Fer) is partially constructed of pressed sheet metal using an innovative system for prefabricated construction, developed by the Belgian engineer Joseph Danly. It is the last remaining example in Belgium of this particular type of industrial heritage, considered to be a precursor to prefabricated modular systems, and one of the few remaining ones in Europe.
Securing Belgian patents in 1887, Danly and his Société des Forges d’Aiseau promoted the system at world and engineering exhibitions. The patented system was also manufactured by French, German and British enterprises, and distributed throughout France via the Haumont forges and foundries.
By the end of the 19th century, the export of the building system to several colonies in Africa and Latin America highlighted the appeal of this innovative modular and demountable construction method, which facilitated quick establishment in very remote areas of the world. Today, some of these structures still exist outside Europe (Congo, Mozambique, Mexico, Costa Rica, Chile and Brazil), where the existing models, primarily of public infrastructure, are cherished and landmarked.
The Iron Castle in Ath is a perfect example of the application of the Danly construction system, where iron is used in both structural and decorative elements. Metal cassettes formed by double skins of profiled metal sheets function as both the façade and load-bearing elements, with floors supported by I-shaped metal girders that ensure horizontal stability.
Rehabilitated after a storm in 1999, the Iron Castle in Ath now features a reinforced framework for fire safety. The ceilings on the building’s ground floor are made of remarkably painted sheet metal. A large part of the rest of the building is an extension with a traditional structure, harmoniously finished on the outside to complement the Danly section, but unexceptional in itself. The Danly section is approximately one third of the existing building.
The Iron Castle in Ath currently belongs to the Federal Property Agency (Régie des Bâtiments) and is no longer in use. The owner is committed to preserving the building but operates within economic constraints. The fear is that if the owner must sell the building and property, a private promoter would demolish the building and reuse its strategically located land for another purpose.
This remarkable witness to both European engineering and Walloon expertise in steel construction is insufficiently valued in Belgium and remains unprotected. The design of this unique building serves as an historical document of the period’s technological and cultural aspirations, reflecting the industrial advances of the period where iron and steel began to influence architectural design and led to innovations in structural engineering and aesthetics, and to the application of new materials. Championed by engineers, architects and professors, the Iron Castle in Ath is the subject of study for researchers in architecture and construction history.
The nomination of the Iron Castle in Ath to the 7 Most Endangered Programme 2025 was made by an Individual Member of Europa Nostra, Professor Laurent Debailleux, Head of the Architecture Department at the Polytechnic Faculty of Mons, who represents the association Château de Fer. The nomination is supported by Europa Nostra Belgium, ICOMOS, Patrimoine Industriel Wallonie Bruxelles, EFAITH, and the owner. Efforts are ongoing to meet the challenges of material vulnerability and degradation of the building, and find an appropriate future for the site.
The Advisory Panel of the 7 Most Endangered Programme “acknowledges the heritage value of the Iron Castle in Ath. Supporting the preservation of this last example of industrial heritage in its country of origin would be relevant not only locally, as it stands as a symbol of the Walloon region’s industrial past, but also within the European context, as it is an important example of the development of European architecture and prefabrication technology at the turn of last century”.