Environmental impacts of Design for Reuse in timber construction using Life Cycle Assessment approach
Main Presenter: Raphaela Ivanica
Co-Authors: Michael Risse Klaus Richter
Due to its various applications and the trend towards a bioeconomy, wood as raw material is becoming increasingly important. Especially in the construction sector, the demand for wood as a raw material is increasing, where it is mainly used in timber panel construction with a high degree of industrial prefabrication. In order to meet the growing demand in the future and to strengthen the transition to a bioeconomy, an efficient use of wood as a resource is inevitable. The cascade use offers a way for wood panel construction to increase efficiency. The implementation of cascade use can be additionally optimized with the closed-loop construction method in the sense of Design for Reuse (DfR). The aim of the DfR concept is to consider the end-of-life (EoL) in the planning phase. This allows the recovery of installed wooden panels as a secondary component for other buildings.
The aim of this study is to examine whether the implementation of the DfR concept in timber panel construction offers ecological advantages using Life Cycle Assessment (LCA) methodology. The environmental impacts of two buildings designed according to DfR principles are compared with those of two buildings using conventional timber panel construction. The focus is set on the reuse of the complete wall elements. The scope of the study includes all stages of the building cycle according to DIN EN 15978, with exception of the use stage. To ensure functional equivalence of both systems, the system extension approach is used.
The implementation of the DfR concept in timber panel construction slightly increases the raw material supply for the first building. Due to an additional remanufacturing process and missing energy benefits from waste incineration in the EoL stage and Module D, the DfR concept results in higher environmental impacts. However, the main benefit of the DfR concept is recovering the building’s elements of the first and the substitution of raw materials for manufacturing and assembling of the second building. In summary, the timber buildings designed according to DfR principles and the cascade use of the timber elements over the life cycle of two building periods show lower environmental impacts than the conventionally constructed buildings.
This study shows the environmental benefits of DfR and cascade use of timber panel construction. In order to represent all pillars of sustainability, further research is required regarding economic and social aspects.