ETH professors Catherine De Wolf and Maria Conen are advocating a radical change in the construction industry. Instead of sacrificing old, energy-inefficient buildings, they advocate their preservation, renovation and expansion. In addition to ecological aspects, the focus is on social and cultural factors. Buildings harbor identities and histories, the preservation of which is essential for city life. Sustainability thus becomes a link between the environment, society and architecture.
Reuse of building materials
A good example is the reuse of glass elements from the external escalators of the Centre Pompidou in Paris as office partitions. The time-consuming dismantling, sorting and reintegration is cost-intensive, but offers enormous ecological benefits through significant CO₂ savings and the avoidance of waste.
Building materials such as wood and concrete have great, previously untapped potential for reuse. While wood is often simply burned, concrete slabs could be cut out and used as wall elements. Although steel beams are recycled, they are usually melted down in an energy-intensive process instead of being reused in a stable form. The challenges lie in technical feasibility, costs and complex planning.
Digitalization and material passports for optimization
Digital tools such as material passports should make it easier to gain an overview of the origin, composition and useful life of components in the future. This will make reuse and dismantling more efficient and transparent. The harmonization of such standards is the subject of research in order to create binding solutions in the industry.
Legal and standardization barriers
Another stumbling block is today’s prevailing standards, which are primarily designed for new buildings and take insufficient account of conversions and the context of existing buildings. This makes renovations and work on existing buildings more difficult from an energy perspective. Laws and regulations must be made more flexible in future in order to promote circular construction methods.
Circular economy as a pioneer for CO₂ reduction
The construction industry is responsible for around 50 percent of resource depletion and considerable amounts of CO₂ emissions. The circular economy significantly reduces these by cutting material costs, waste and energy consumption through reuse and modular construction. Deconstructability through bolted or plugged rather than glued connections is key here.
Challenges and future prospects
The biggest challenge lies in the effort involved in dismantling and reusing materials and finding buyers for reused materials. The lack of comprehensive market structures makes widespread implementation difficult. This is where initiatives such as digital marketplaces and the involvement of specialized engineering expertise come in.
Modular construction and flexible usage concepts, such as the use of less well-insulated buildings as museums, show viable prospects for the future. The young generation of students and researchers at ETH and other institutes in particular are driving innovation, which gives hope for a more sustainable construction industry.
