Systems for Reuse, Repurposing and Upcycling of Existing Building Components Colin Rose Thesis submitted in partial fulfilment of the requirements of the Doctorate of Engineering at University College London Faculty of Engineering Department of Civil, Environmental & Geomatic Engineering Centre for Urban Sustainability and Resilience April 2019 1 2 Declaration I, Colin Rose, confirm that the work presented in this thesis is my own. Where information has been derived from other sources, I confirm that this has been indicated in the thesis. 3 4 Abstract The construction industry uses natural resources intensively, and causes significant carbon emissions in processing resources to supply useful materials and components. Demolition generates considerable physical waste, accompanied by wastage of the impacts embodied in existing building components. This project explores the failure to capitalise on these embodied impacts, and adopts a mixed methods approach to develop interventions and identify potential mechanisms for change. The main contributions of the thesis are: Firstly, an exploration of the notion of ‘component management’. This challenges the assumption that components removed from the building stock must either be: a) directly reused, which can often be impractical, and is rarely given due attention, or b) sent to waste management, which wastes embodied impacts. Instead, the role and implementation of repurposing and upcycling are described, alongside a procedure for comprehensively checking the practicality of direct reuse; Secondly, the development of an urban-level ‘triage’: a process to separate out components for reuse, repurposing and upcycling, from those for which downcycling or energy recovery are the best option. Key to the triage is an information system; the thesis reviews current means of understanding existing buildings as material banks and presents a new approach to gathering this information; Thirdly, a proposal for an innovative manufacturing enterprise using secondary timber in a new product: cross-laminated secondary timber. This provides an exemplar case study of the potential for industrial-scale upcycling. A proof of concept study is presented, with a preliminary examination of technical feasibility and leading the way for additional investigation of socio- economic and environmental sustainability, and, ideally, future pilot- and commercial-scale implementation. The implications of this product case study are synthesised with the other parts of the thesis in a discussion of areas for future research, policy and practical action to evolve a more nuanced and sustainable management of existing building components. 5 Impact statement The impacts of the research range from immediate benefits in the local context of the project, through, for instance, facilitating the exchange of materials discarded from construction sites to new businesses and community projects in the London Borough of Tower Hamlets, to incremental take-up of ideas that could have an impact on an international level. Investigations into the urban-level management of existing building components have led to policy recommendations that could be adopted by cities in many contexts. These have been disseminated through articles published in international peer-reviewed journals and at conferences and academic workshops around Europe. Co-authors of journal papers and conference contributions have included academics, members of the industrial sponsor organisations and a practising engineer. Collaboration with another practising engineer led to the dissemination of a product innovation, cross-laminated secondary timber (CLST), through public engagement at the Victoria & Albert Museum in London. The collaborative approach taken in the project has involved supervision of six Master’s students’ dissertations relating to CLST. A further Master’s student produced a video based on this project’s initial findings, and intended to raise awareness of construction waste, which has been viewed more than 5,500 times on YouTube. Development of the concept of CLST has included a commercial pilot project that was carried out collaboratively with an architectural firm, a timber reclamation contractor, a reclaimed timber stockist and a new reuse enterprise. The physical outcomes of the pilot are in use in a co- working space. The non-physical outcomes include forming new connections in a reuse network, generating work for local carpenters and generating workshop rental income for the reuse enterprise. Publications arising from the research have sought to open new avenues for further thought by other researchers and identify specific areas of further research. The presentation of the idea of CLST has attempted to draw attention to a hitherto unexamined use of secondary timber and indicate the steps that will need to be taken to move the concept towards full-size pilot production and commercial implementation. Timber is a ubiquitous building material and, with incremental progress towards proving feasibility, plants producing CLST could come to serve regions in many parts of the world. In the long-term, this could lead to great environmental benefits (savings in embodied carbon emissions; avoidance of waste disposal), social benefits (employment in reclamation and manufacturing close to urban areas) and economic benefits (extracting greater value from discarded materials). Given that the Doctorate of Engineering is intended to be applied in an industrial context and to have impact both within and outside of academia, more detail of the impacts of the project are provided in the main body of the thesis. 6 Acknowledgements I would like to thank my academic supervisor, Professor Julia Stegemann, for recognising in my original research proposal a topic worthy of investigation; for great conversations; and for backing me all the way. Many people have offered support in this project, and I am very grateful to them all. Of my colleagues at the Centre for Urban Sustainability and Resilience, I would like to thank Kell Jones for being a brilliant sounding board, and Victoria Maynard, Alejandro Romero, Loretta Tann and Dr Ine Steenmans for your help, enthusiasm and input. The UK Engineering and Physical Sciences Research Council funded this research, with co- funding from Poplar HARCA and Tower Hamlets Homes. Many thanks to my industrial supervisors: Chris Johnson and Nick Martin at Poplar HARCA, and Nick Gopaul and Will Manning at Tower Hamlets Homes. Thanks to Paul Augarde at Poplar HARCA and Jamie Carswell at Tower Hamlets Homes for helping to instigate the project. Thanks to the Development and Regeneration Team and the Accents Team at Poplar HARCA and all of the many people who gave their time or became embroiled as case study participants. Thanks to Dr Philippe Duffour and Dan Bergsagel for offering your expertise. I am grateful to my parents, Malcolm and Barbara Rose, for helping me to become the kind of person who undertakes a project like this; and for all the love and support. Thanks to Joyce Daly for providing me with a desk and an ideal working environment, when London became too much. And finally, thanks to Jessica Daly for sticking with me through this whole process – I know it’s been difficult. Thanks for believing in me, doing so much to make our lives work, and being my best friend and number one fan. 7 Table of contents Abstract 5 Impact statement 6 Acknowledgements 7 List of tables 11 List of figures 13 List of abbreviations 16 Preface 17 1 INTRODUCTION 18 1.1 The problem with the construction industry’s use of materials 18 1.1.1 The construction industry and the fundamental processes of construction 18 1.1.2 Global impacts of flows of construction materials 18 1.1.3 Risks and resilience in the construction industry connected to its resource use 21 1.2 Responses to the stated problem 21 1.2.1 Areas of focus to address construction industry impacts 21 1.2.2 Design of new additions to building stocks 22 1.2.3 Management of existing building stocks 26 1.2.4 Management of building components removed from stock 28 1.3 Project aim and objectives 30 1.3.1 Longtermgoalandprojectaim 30 1.3.2 Research scope, objectives and thesis structure 31 1.3.3 Publications arising from this research 33 2 ACADEMIC BACKGROUND 36 2.1 Introduction to literature review 36 2.2 Quantifying C&D waste generation 36 2.2.1 Distinguishing construction waste and demolition waste 36 2.2.2 C&D waste generation and material recovery in grey literature 37 2.2.3 C&D waste generation and projections in academic literature 38 2.3 Order of preference for C&D waste management options 38 2.3.1 The waste hierarchy 38 2.3.2 The definition of waste 40 2.3.3 The definitions and benefits of prevention and reuse 40 2.3.4 Problems with recycling and downcycling 42 2.4 Increasing reuse: barriers and strategies to overcome them 43 2.4.1 Review of barriers reported in the literature 43 2.4.2 Systemic nature of the problem 50 2.4.3 Industry-focused strategies to address reported barriers 51 2.4.4 Reused material marketplaces 55 8 2.4.5 Macroeconomic, policy and regulatory interventions 56 2.5 Repurposing, upcycling, and the assessment of waste management options 59 2.5.1 The need for repurposing and upcycling 59 2.5.2 Life cycle assessment for waste management decisions 60 2.5.3 ‘Impact reduction potential’ applied to C&D waste management decisions 61 2.6 Summary and gaps in understanding 64 3 METHODOLOGY 66 3.1 Overview of research design 66 3.2 Research paradigm 67 3.2.1 Background to research philosophies