The climate policy targets meanwhile set by the EU and many member states to reduce or at least contain global warming have a direct impact on the future assessment of buildings and construction methods. While in the past decades the focus was mainly on measures that reduce the heating energy and final energy demand in the coming years greater attention will be paid to a building’s CO footprint over its life cycle. Since this footprint is an extremely complex issue that is influenced by many factors, its assessment is always the result of precise or in fact less precise input data. In addition, there are political influences that use striking, but per se incomplete results to influence a development which is or is assumed to be in line with a self-imposed political credo.
Study compares enviromental aspects of timber and aerated concrete as a building material
It is often claimed that switching from the con-struction method using mineral building materials predominating in Europe to a timber construction method can make a key contribution to successfully completing the path to a decarbonized society. This assumption is based on the simple thought that one cubic meter of wood can store about one ton of CO2 during its growth. That is all you need to know. Given that the widely used mineral building materials, e.g. concrete, bricks and autoclaved aerated concrete, are made of raw materials that have a very high CO2 impact, it is suggested that these building materials can no longer meet the future requirements. The as-sociated debate of how to reconcile the use of wood, reforestation and the future demand for conifers that procure most of the construction timber with the protection of forests is, of course, another side of this challenge.
In a study  by the German Association for Masonry Construction (Deutsche Gesellschaft für Mauerwerksbau – DGfM) in cooperation with LCEE Darmstadt, many of the supposedly clear climate-relevant advantages of timber construction have already been reduced to absurdity in the context of a life cycle assessment (LCA). As the study was conceived as a kind of cross-sectional approach for all main types of masonry used in Germany, the concrete performance of individual masonry types cannot be directly derived from it. Together with LCEE Darmstadt, Xella Technologie- und Forschungsgesellschaft mbH therefore repeated this assessment for a typical single-family home made of autoclaved aerated concrete and compared it with an imaginary identi cal timber building taking current changes in energysaving legislation in Germany (Gebäudeenergiegesetz (Buildings Energy Act) – GEG) into account and using the new Ökobaudat_2021 database […].
The article will be published in issue 3/2021 of AAC Worldwide.