The increasing awareness of the finite nature of material and energy resources in the context of the challenges of climate change poses new questions and tasks for the construction industry. Studies show that this industry alone is responsible for 40 per cent of waste, 40 per cent of primary energy resource consumption and 40 per cent of carbon emissions worldwide. The rapid growth of cities in particular is contributing to this phenomenon. According to United Nations calculations, about 55 per cent of the world’s population live in cities today. By 2050, this figure will reach around 68 per cent – there will be around 6.34 billion city dwellers. This will present enormous challenges in terms of resource consumption in the building industry, as we construct new buildings and develop new infrastructure.
Currently, our economic system is primarily linear. Raw materials are extracted, used, and become part of our built environment. When no longer needed, they become waste, having reached the end of the consumption chain. However, scientists, researchers and experts have long been calling for a mind shift towards a “circular economy” in which raw materials are given a new usage when they no longer fulfil their original purpose. In cities in particular, there is a dense concentration of resources that can be incorporated into a cycle of value creation using urban mining or material harvesting, facilitating new business models and making a sustainable and climate-friendly economy possible. To actively implement this, a new legal framework is needed that encourages a circular economy and regulates important aspects such as warranty.
Incorporating building materials into material cycles used to be a widespread practice in construction. Until around 200 years ago, the most commonly used materials were stone, wood, lime, clay and plant fibres – most of them highly robust. These natural building materials were either reused or returned to the natural material cycle through processes of decay. Today’s building materials are complex, often consisting of multi-layered components and including different constituent materials and coatings, made, for example, of plastics, which are often difficult to reuse and after demolition frequently end up in a hazardous waste landfill.
Back in 2016, the United Nations adopted the Sustainable Development Goals, which call for countries to move towards a sustainable circular economy and sustainable urban development. On 16 September 2020, President of the European Commission Ursula von der Leyen therefore gave top priority to the circular economy with the aim of achieving the 2050 climate targets: “The circular economy, including new waste and recycling laws, will represent half of the EU’s effort to achieve net-zero carbon emissions by 2050”.
The exhibition at the HDA presents studies and practical examples of architectures, conversions and system cycles that impress with their high design quality as well as their genesis from reused material resources.