‘It is absolutely unnecessary, even detrimental, to embellish the façades’
Authors: Van de Voorde Stephanie , Fivez Robby 
Published: November 2024

Following World War I, Belgium faced a severe housing crisis, necessitating a comprehensive reform of social housing policy. Established in 1919, the National Society for Cheap Housing (Nationale Maatschappij voor Goedkope Woningen en Woonvertrekken, nmgww) aimed not only to repair material damage but also to address new social and societal demands. However, financial resources were limited, while there was also a severe shortage of (traditional) building materials and skilled labour. Progressive architects attempted to create a new, socially engaged architecture with a modernist vocabulary through the nmgww. They also advocated for the application of alternative building methods that had the added advantage of being financially favourable. The lack of expertise and experience with these alternative methods prompted the nmgww to set up an experimental project at Het Rad in Anderlecht in 1920. It entailed the construction of some sixty houses, employing eighteen different building systems. While most of these systems used concrete blocks, three utilized a prefabricated skeleton, and two opted for cast-in-situ concrete using monolithic casting systems. Nearly all utilized ‘lean concrete’, a type of concrete with a low cement content. Furthermore, in most cases part of the aggregate was replaced with industrial waste products to reduce costs and improve thermal properties. The intention was to perform an extensive evaluation and objective comparison of the different building systems. Yet even before the experiments had been concluded, the nmgww started to actively promote the German casting system Non Plus. For example, it invited local housing associations to participate in a study trip to Merseburg near Berlin to familiarize themselves with the system. Successfully, as it turns out as the system was subsequently used in the garden suburbs of Klein Rusland in Zelzate (1920-1923) and La Cité Moderne in Sint-Agatha-Berchem (1922-1925). The two districts were designed respectively by the architects Huib Hoste and Victor Bourgeois  in a modernist idiom.
The literature often refers to the economic benefits of the Non Plus system and to the impact of construction techniques on the aesthetics of these garden suburbs. However, in-depth research shows that the relationship between economic, technical and aesthetic aspects is not so straightforward: concrete was not necessarily cheaper than brick, while the plaster exterior often concealed a variety of systems. Moreover, both garden suburbs were initially designed in brick, indicating that there is no causal link between the material and the design language. It was not long, however, before the alternative building systems in lean concrete, particularly the monolithic casting systems, were abandoned. After 1926, as a result of political power shifts, the focus switched to small-scale projects and alternative building systems lost their scale-based economic advantage. Yet the experiment with alternative building practices, however brief, was an important phase in Belgian architectural and construction history. Projects like Het Rad and the modernist garden suburbs in cast-in-situ concrete show the interrelationship between societal, social, political, cultural and economic ambitions on the one hand, and the evolution of building culture on the other.