More circular construction waste in Brussels

In Brussels, construction waste represents about 650,000 tonnes per year. At European level, the construction sector accounts for half of the extraction of resources. Each building project has an impact on the environment that will have to be drastically reduced in the coming years to reach carbon neutrality by 2050.

The construction and renovation value chain entails various actors, such as the architect, the public or private client, the company, logistics, the craftsman. Given the current challenges, such as reducing waste production and promoting the circular economy, each development within the sector must be addressed with a specialized approach.

One of the levers that has been studied for several years in Brussels is the audit of the reuse of materials before demolition or rehabilitation of a building. This audit makes it possible to identify the materials, characterise them, locate them and anticipate their re-use or recycling on or off site in the construction/rehabilitation project. Some Brussels actors are recognised at European level for their expertise in this field.

These audits are not mandatory for the moment but should become so in the coming years. Today, during these audits, site visits and expert analyses make it possible to formalise reports consisting of Excel sheets listing the characteristics of the materials and their location in the building. This is a very good start, but it is rather small-scale and does not yet allow for the industrialisation of the process or the pooling of sufficient data to reach a critical mass that will turn the sector around.

Other approaches are emerging, such as the use of scanners and drones to speed up visits, and the organisation of open source databases to encourage the creation of a regional database and the exchange of information. If such a database on building materials were to be set up, it could make it possible to create the first bricks of a Brussels digital twin, where each actor could identify the deposit of material in stock and anticipate its use in his construction/rehabilitation project. This database must reach a critical mass so that materials are available at all times (with a minimum number of construction sites in progress in the database). Only then can construction waste be integrated into the reuse and recycling cycles.

For the time being, the re-use audits carried out by project leaders concerned with limiting their environmental impact are not yet shared, limiting the creation of this common database and the achievement of this critical mass. However, this future is technically possible, the Brussels actors see the interest in it for some, but a collective approach to deploy it remains to be formalised.