Material stocks of the non-residential building sector: the case of the Rhine-Main area

The building sector is known to have the largest inventories of materials in industrialized societies. In comparison to residential buildings, non-residential buildings (NRBs) are much more diverse in function, components and their respective materials. In order to provide insights in material stocks of the non-residential area, this study focused on the case of the Rhine-Main area, a metropolitan region holding extensive stocks of office buildings as well as factory, logistic and other NRBs. The investigation covered analysis of spatial data and examination of single buildings. The structure of the NRB sector was comprehensively characterized in a case-study area as to function and age-classes of existing buildings in terms of building gross volume. The two types “factory” and “commercial/retail and services buildings” accounted for about half of the existing buildings. As to age, about one third of the buildings was found to originate before 1948. This indicates the high importance of renovation activities as a prerequisite for the continuous use of NRBs. Specific material contents of buildings were assessed, showing a large variety. Combining spatial and building related information, a methodological approach was developed which provides area-wide information on material stocks incorporating the allocation to function and age-class of NRBs. This approach may be used for regional estimation of potentials of secondary resources and for Material Flow Analysis in order to estimate potentials and flows of secondary resource.