Method for determining the material composition of buildings prior to demolition | Methode zur Bestimmung der Materialzusammensetzung von Gebäuden vor dem Abbruch

A basic prerequisite for efficiently recycling waste from building demolitions and determining material-specific recycling rates is detailed knowledge of the buildings’ (as future sources of waste) material composition. The following article discusses a method for characterising the material composition of buildings prior to their demolition, and assesses the method’s applicability on the basis of case studies.The method is based on the analysis of available documentation (e.g. blueprints, assessment reports etc.) for the respective building on the one hand, and on onsite inspection and selectively collecting samples from the building on the other. The results are subsequently compared with the data provided by the demolition company after demolition.We also present four case studies and their results. With regard to the method, the results show that the documentation is particularly well suited to quantifying composite materials like brick, concrete, sand and grit, and for partly quantifying metals (steel) and wood. However, onsite inspection and selectively collecting samples are called for in order to locate and measure comparatively low-volume materials like other metals (e.g. copper and aluminium), wood and various plastics.The material intensity of the buildings examined ranges from 270 to 470 kg pro m³gross volume, though the relative percentages of materials vary greatly between different types of building.Additional case studies are intended to continually improve the available data on the material composition of buildings from different construction periods and with different functions. In this regard the goal is to generate specific values for the material composition of the respective types of building, which will allow us to make accurate estimates, both with regard to the total volumes of different materials in Vienna’s buildings with the help of GIS (geographic information system), and regarding the amounts and types of waste that will be produced by future demolitions.