Climate impacts of wood/ timber as a building material – investigated on three urban quarters in Germany (CIW)

Abstract

Due to the current discussion about the shortage of resources and the excess of greenhouse gas emissions, timber construction is experiencing a renaissance in Germany. As a renewable resource, wood can replace emission-intensive building materials and, if left long-term in the construction, lead to negative balances, i.e. carbon sinks at the construction phase (LCA phase A1-A3). This means that more carbon could be stored in the construction than is emitted during production. This study analyses different buildings ranging from row houses to high-rise buildings that are envisioned as envisioned as envisioned as envisioned as envisioned as timber construction of three so called timber-quarters (Holzbauquartiere). For all buildings, the current design/ construction, a conventional as well as a timber+ construction (maximum possible timber use in construction) variant have been evaluated. The calculations were conducted with eLCA the LCA tool of the Bewertungssystem Nachhaltiges Bauen (BNB) (German Green Building System) and the data sets of the German ÖKOBAUDAT[11]. The results are given per m2 gross floor area per user, per building and per neighbourhood. The investigations show the importance of the material choice regarding the climate gas emissions of the buildings and how large the proportion of wood must be in order to design the building envelope (KG 300 (cost group for architectural elements) in a climate gas neutral way. Planning parameters for a climate gas neutral design and construction of buildings are derived from the analysis.