Wood in sustainable construction - a material perspective Learning from vernacular architecture

Aalto University, P.O. Box 11000, FI-00076 Aalto www.aalto.fi Author Atsushi Takano Name of the doctoral dissertation Wood in sustainable construction a material perspective Learning from vernacular architecture Publisher School of Chemical Technology Unit Department of Forest Products Technology Series Aalto University publication series DOCTORAL DISSERTATIONS 97/2015 Field of research Wood Material Technology / Wood Architecture Manuscript submitted 1 April 2015 Date of the defence 4 September 2015 Permission to publish granted (date) 23 June 2015 Language English Monograph Article dissertation (summary + original articles) Abstract Traditionally, vernacular buildings were constructed based upon a deep understanding of the surroundings and the features of locally sourced materials. This wisdom led to a rational building composition and appropriate material selection, which ensured adequate living conditions and proper building life cycle, without any advanced technologies. In the discussion about reducing the environmental impacts of a building, there should be useful ideas to be taken from traditional solutions for the further development of modern buildings. A life cycle perspective is nowadays becoming more significant for comprehensive building analysis as the distribution of the environmental impacts over a building life cycle change. In such a context, building material selection is an important factor. Wood products have lately attracted attention as promising construction materials due to their unique environmental properties. This study investigated the optimal use and development of wood products in sustainable construction in comparison to other building materials, based on life cycle assessment method. With regard to learning from vernacular buildings, a holistic analysis of wood in construction was carried out. In this dissertation, first the methodological issues relating to the fair assessment of wood products and wood construction based on the current normative standards and assessment data were discussed. Secondly, wood in sustainable construction was discussed according to ten principles in terms of appropriate building material selection over the building life cycle. This study demonstrated that there are both strengths and weakness to the use of wood in sustainable construction. In this sense, the importance of diverse perspectives to building materials has been highlighted. It was also discussed that wood may contribute to the environment more positively when it is used more. A reduction in consumption (e.g. energy) and emissions (e.g. CO2) has thus far been the principle behind mitigating environmental impacts. In this context, for instance, a CLT (Cross laminated timber) framed building would not be preferable since it requires a large amount of wood, resulting in high embodied energy. However, on the other hand, that gives significant environmental benefits (e.g. energy recovery) to the building. In this case, by optimising the weaknesses (high embodied energy) and maximising the strengths (environmental benefits), the greater use of wood may improve the environmental profile of a building. This would be a paradigm shift from the current approach to the environmental problems. In that sense, wood seems to have significant potential. It would be important to consider a specific approach and use for wood in construction based upon the proper understanding of their characteristics as practiced in traditional buildings.Traditionally, vernacular buildings were constructed based upon a deep understanding of the surroundings and the features of locally sourced materials. This wisdom led to a rational building composition and appropriate material selection, which ensured adequate living conditions and proper building life cycle, without any advanced technologies. In the discussion about reducing the environmental impacts of a building, there should be useful ideas to be taken from traditional solutions for the further development of modern buildings. A life cycle perspective is nowadays becoming more significant for comprehensive building analysis as the distribution of the environmental impacts over a building life cycle change. In such a context, building material selection is an important factor. Wood products have lately attracted attention as promising construction materials due to their unique environmental properties. This study investigated the optimal use and development of wood products in sustainable construction in comparison to other building materials, based on life cycle assessment method. With regard to learning from vernacular buildings, a holistic analysis of wood in construction was carried out. In this dissertation, first the methodological issues relating to the fair assessment of wood products and wood construction based on the current normative standards and assessment data were discussed. Secondly, wood in sustainable construction was discussed according to ten principles in terms of appropriate building material selection over the building life cycle. This study demonstrated that there are both strengths and weakness to the use of wood in sustainable construction. In this sense, the importance of diverse perspectives to building materials has been highlighted. It was also discussed that wood may contribute to the environment more positively when it is used more. A reduction in consumption (e.g. energy) and emissions (e.g. CO2) has thus far been the principle behind mitigating environmental impacts. In this context, for instance, a CLT (Cross laminated timber) framed building would not be preferable since it requires a large amount of wood, resulting in high embodied energy. However, on the other hand, that gives significant environmental benefits (e.g. energy recovery) to the building. In this case, by optimising the weaknesses (high embodied energy) and maximising the strengths (environmental benefits), the greater use of wood may improve the environmental profile of a building. This would be a paradigm shift from the current approach to the environmental problems. In that sense, wood seems to have significant potential. It would be important to consider a specific approach and use for wood in construction based upon the proper understanding of their characteristics as practiced in traditional buildings.