Abstract :
[en] Wallonia, like many other European regions, is characterized by a diverse existing residential built environment, both urban and rural. This building stock is primarily comprised of single-family houses, along with a significant number of old historic and traditional buildings. Considered as energy intensive, it requires energy renovation by 2050 to meet both European and Walloon objectives regarding building energy efficiency as well as a rising focus on circular economy principles and sustainable resource and waste management.
Energy renovations on this building will intensify, leading to a substantial increase in demolition waste production. While these wastes represent 39% of all waste in Wallonia with significant environmental impacts , they are also considered, within an urban mining framework , as a deposit of material resources. They can be reused either directly in buildings or repurposed as raw materials in production cycles. Urban mining studies primarily center on residential buildings, using top-down methodologies based on statistical data analysis. Typically, they focus on a single material such as aggregates, sand, or concrete. However, despite their prevalence in old traditional and historic buildings, wood, stone, bricks, and tiles have not received thorough examination. Moreover, few studies have analyzed the entire deposit present in the existing traditional residential buildings stock and/or the influence of energy renovation on waste flows, especially due to a lack of data and methods.
Wallonia lacks detailed data with a high level of granulometry regarding its residential building stock, the existing material deposit, and the demolition waste flows. Collecting such data can only be achieved through a bottom-up approach involving in-depth study of representative case studies of various building types and statistical analysis of renovation operations. Due to the diversity of the old Walloon residential building stock, these studies are time-consuming, resource-intensive, and expensive. It is therefore urgent and essential to focus on developing an on-site, rapid, and reliable method of acquiring detailed data on existing buildings.
In this context, the URMIBALI research project aims to develop a method for rapidly acquiring detailed data to inventory and quantify the materials deposit present in historic and traditional residential building stock in Liège. This method will be based on both six case studies, digital documentation technologies commonly used in the field of heritage and existing historical and archaeological knowledge about this specific building stock, its construction techniques, and materials. The innovation lies in the bottom-up and interdisciplinary approach, the multi-material focus, and the potential for transferability and generalization to other types of built environments and cities. This knowledge is essential for implementing circular practices in the Walloon and European construction sector and integrating them with energy renovations.
This contribution first outlines the methodological approach and presents the results of the theoretical inventory of building-material deposits. It then describes the documentation method developed for these materials, which combines artificial intelligence with dedicated digital tools. Finally, it discusses the initial data obtained using this method and compares them with the theoretical inventory.
