Public defence in Building Technology, M.Sc. (Tech) Yishu Niu

Title of the thesis: Life-cycle analysis in timber construction - environmental impact and decision-making

Thesis defender: Yishu Niu
Opponent: Prof. Chiara Piccardo, KU Leuven, Belgium
Custos: Prof. Gerhard Fink, Technical University of Munich, Germany

The construction industry is a major contributor to climate change, highlighting the need to use sustainable and renewable materials. Timber has gained increasing recognition as a promising alternative to conventional carbon-intensive materials such as concrete and steel. Meanwhile, life cycle carbon footprint reporting within the construction sector has gained popularity, and, in some cases, become mandatory. The relevant life cycle performance evaluation of timber construction and its application for decision-making require further investigation. 

This dissertation utilizes life cycle assessment (LCA) as the primary methodology, to investigate the benefits and obstacles of timber construction from sustainability perspective. The study encompasses both upfront and post-use of timber use in construction. The findings highlight the large variation in existing literature of LCA application on timber projects and identify the potential of using environmental product declarations (EPDs) to reduce the variability of LCA. Both the potential and challenges of LCA in early-stage decision-making for timber projects are addressed. A proposal for integrating LCA into the risk-informed optimization approach is introduced. Furthermore, the substantial benefits of cascading timber in reducing climate change impacts from a life cycle perspective are highlighted, and a conceptual framework of wood ecosystem is proposed to promote circular economy. 

The results of this dissertation encourage the utilization of LCA as an essential tool in environmental responsibility across both early and late project stages, as well as imply a paradigm shift in stakeholders’ decision-making criteria, from a typical short-term-oriented and cost-focused approach to a more holistic and sustainability-oriented framework. The findings may also inform the development of policies and regulations related to climate change and sustainability.

Keywords: life cycle assessment, timber, carbon footprint, circular economy, decision-making

Thesis available for public display 7 days prior to the defence at Aaltodoc. 

Contact information: Yishu Niu, yishu.niu@aalto.fi