Thinking consciously about how natural resources are used has always been a core topic at the DGNB. Right from the beginning, the DGNB has offered a certification system that favours a holistic approach to carbon footprints. Therefore, this has always involved not only the conscious selection of building materials according to their composition and origin, but also a methodical assessment of the ‘reclaimability’ of individual residual materials – all based on strict criteria, criteria that have thus become established in the market.