Designing for disassembly and reuse are currently prohibitively expensive
Created on 19-10-2023
Design, planning and building
A significant challenge preventing the realisation of circular housing is the high costs linked to designing for disassembly and reuse. This a significant barrier faced by social and affordable housing providers, which includes public and private housing developers. Utilising life cycle costing based on longer return on investment periods proves instrumental in incentivising developers towards environmentally sustainable design. Other practical tools include take-back schemes, leasing models, and government subsidies to strategically alleviate disassembly costs. Additionally, leveraging tools Building Information Modelling (BIM) optimises disassembly planning, identifying reusable components and assessing ecological impact. Embracing systems thinking ensures comprehensive solutions. Collaborative efforts between academia, industry, and policy-makers are crucial. Grounded in scientific methodologies, these collaborations are essential to facilitate the transition toward a financially viable, sustainable construction paradigm.
System knowledge
Actors
Housing developers
Non-profit and for-profit housing organisations that undertake various tasks, such as the construction and management of housing.
Housing authorities
A government agency, usually at the municipal, county, or state level, provides and oversees various housing-related programmes and services.
Social housing provider
An entity, often a governmental or non-profit organisation, responsible for offering affordable housing options and related services to individuals or families in need within a community or society.
Construction companies
Method
Systems thinking
Systems thinking is an approach to understanding and solving complex problems that looks at the big picture and the interactions between the different parts of a system, rather than focusing on isolated components or events. It also considers the relationships and connections between these components to understand the system as a whole.
Interdisciplinary collaboration
Teams from different disciplines or fields work together to tackle complex problems, find innovative solutions and develop a broader understanding of a particular issue. This approach recognises that many real-world challenges cannot be adequately addressed within the confines of a single discipline or field.
Target knowledge
Topic
Environmental sustainability
The responsible and balanced use of environmental resources to ensure that they are conserved and available for present and future generations. It involves protecting and conserving the natural environment while promoting human well-being.
Dimension
Environmental
This dimension focuses on understanding and addressing the environmental challenges and concerns related to human activities and their impact on the natural world.
Level
Building
The structure, project or development that is directly impacted by the various building regulations.
Transformational knowledge
No references
Related vocabulary
Affordability
Sustainability
BIM
Design for Dissassembly
Area: Policy and financing
Housing is usually deemed unaffordable when it consumes more than a set percentage of a household's monthly income. The Eurostat[1] and the OECD[2] follow this threshold approach and define households overburdened with housing costs as those spending more than 40% of their disposable income on housing.
However, this indicator fails to capture financial hardship, particularly among lower-income households. In fact, lower-income households may be spending less than 40% of their income on housing and yet failing to meet adequate consumption levels for other goods. As a response, the residual income approach ascertains housing (un)affordability by defining a minimum level of consumption for a set of goods according to particular household types. The residual income approach builds on consumption data to define the minimum level of income necessary for a household to survive after housing costs. The main shortcoming of this approach is that relies on subjective measures of what constitutes the necessary minimal expenses for a household.
These two definitions of affordability navigate two tensions 1) between housing and other types of consumption and 2) between the individual conceptions and what is affordable and what government considers to be affordable (Haffner & Hulse, 2021). More recently, scholars have emphasized the multi-faceted nature of affordability to include commuting and transport costs together with energy costs (Haffner & Boumeester, 2015). Other approaches focus on supply-side measures, for instance on the share of the housing stock that a household can afford (Chung et al., 2018).
Evolutions in the measurement of affordability bear witness to the complexity of housing systems. Affordability is not only dependant on housing consumption but also housing supply, particularly in inelastic markets where providers have considerable power. At the same time, displacement pressures and rising energy costs in an older and inefficient stock add pressure on households to access affordable housing.
References
Chung C., Evangelou N., Geyer J., Quint R., Keith I., Coates D., Daula T., Frumkin S., Leventis A. v, Doerner W. M., Roderer D., & Barba M. (2018). A New Home Affordability Estimate: What Share of Housing Stock Can Families Afford?. FHFA Staff Working Papers 18-04, Federal Housing Finance Agency.
Haffner M., & Boumeester, H. (2015). Housing affordability in the Netherlands: the impact of rent and energy costs. Journal of Housing and the Built Environment, 30(2), 293–312. https://doi.org/10.1007/s10901-014-9409-2
Haffner M., & Hulse K. (2021). A fresh look at contemporary perspectives on urban housing affordability. International Journal of Urban Sciences, 25(S1), 59–79. https://doi.org/10.1080/12265934.2019.1687320
[1] https://ec.europa.eu/eurostat/web/products-datasets/-/tessi165
[2] https://www.oecd-ilibrary.org/sites/624ee022-en/index.html?itemId=/content/component/624ee022-en#section-d1e6271
Created on 15-07-2021
Read more ->Area: Community participation
Contemporary scholars generally accept the multidimensional understanding of sustainability - social, political, economic, cultural and environmental amongst other dimensions – but the concept used to be defined more narrowly as the ‘conservation of natural resources’ and the ‘restoration of ecological balance’ (Meadows et al. 1972). While the ‘Brundtland Report’ was instrumental in broadening the definition and bridging the environmental and economic dimensions (WCED 1987), it was Elkington who stressed the social dimension in the ‘triple bottom line’ of ‘people, planet, profit’ (1998). However, the role of community participation as an elementary part of social sustainability was only established after the turn of the millennium by Giddings et al. (2002). They emphasised the participation aspect of procedural equity “so that people are able to shape their own futures” (ibid., p.194). Dempsey et al. (2011) drew upon this contribution when they considered urban sustainability from a community approach and concluded that communities thrive upon social interaction between community members, organisational initiative through collective groups and networks, the relative stability of a neighbourhood in terms of net migration and turnover, a positive identification or sense of place and the level of trust that follows from a perception of safety. These factors are summarised by Dixon and Woodcraft (2013, p.475) as “the extent to which a neighbourhood supports individual and collective well-being (…) It combines design of the physical environment with a focus on how the people who live in and use a space relate to each other and function as a community”. While most community participation researchers look into social sustainability on the neighbourhood level, Putnam’s book ‘Bowling alone’ (2000) described how a lack of social capital, here understood as strong civic participation and localised empowerment, could prevent collective action and undermine democracy on the macro-level.
References
Dempsey, N., Bramley, G., Power, S., and Brown, C. (2011). The social dimension of sustainable development: Defining urban social sustainability. Sustainable development, 19(5), 289-300.
Elkington, J. (1998). Partnerships from cannibals with forks: The triple bottom line of 21st‐century business. Environmental quality management, 8(1), 37-51.
Giddings, B., Hopwood, B. and O’Brien, G. (2002). Environment, economy and society: fitting them together into sustainable development. Sustainable development, 10, 187–196.
Meadows, D.H., Meadows, D.L., Randers, J. and Behrens, W.W. (1972). The Limits to Growth. Washington DC: Potomac Associates.
Putnam, R.D. (2000). Bowling Alone. New York: Simon and Schuster.
Woodcraft, S. B., and Dixon, T. (2013). Creating strong communities–measuring social sustainability in new housing development. Town and Country Planning Association, 82(11), 473-480.
World Commission on Environment and Development (WCED). (1987). Our Common Future. Oxford: Oxford University Press.
Created on 21-07-2021
Read more ->Area: Design, planning and building
Building Information Modelling (BIM) is the process of creating a set of digital representations which consists of both graphical and non-graphical data for the entire building cycle (Eastman et al., 2011). This process involves documenting, gathering, organising, and updating this information throughout the whole life cycle of a building from conception to demolition (Eschenbruch & Bodden, 2018). Beyond the demolition stage BIM can also support circular principles; managing the re-use, recovery, and recycling-potential of a building (Akbarieh et al., 2020; Xue et al., 2021). Whilst the concept of BIM as a process is supported by the International Organisation for Standardisation in ISO 19650-1:2018 (ISO, 2018), the National BIM Standard describes BIM as a digital technology (NBIMS-US, 2015). Despite the origins of BIM dating back to the 1970s, it did not become widely adopted by the Architecture, Engineering and Construction (AEC) industry as a computer design tool until the 2000s (Costa, 2017).
The digital building information model uses intelligent objects to store information in the form of three-dimensional geometric components along with its functional characteristics such as type, materials, technical properties, or costs (Eschenbruch & Bodden, 2018). This model forms the basis of a shared knowledge resource to support the various digital workflows of multidisciplinary stakeholders (Chong, Lee and Wang, 2017; Barile et al., 2018). Moreover, it serves the purpose of visualisation, clash detection between different building components, code criteria checking, environmental analysis, and cost estimation to name a few (Kamel & Memari, 2019; Krygiel & Nies, 2008). Therefore, utilising BIM can improve construction accuracy and enhance the built asset’s performance (Kubba, 2017; Love et al., 2013). The building information model facilitates the knowledge transfer between experts and project participants to satisfy end-user needs and support early-stage decision-making (Chong et al., 2017; Lu et al., 2017). Therefore, BIM can be considered a transdisciplinary practice as it communicates AEC, computation, and science (Correia et al., 2017).
In the AEC industry implementing BIM involves several stages, which are known as BIM maturity models. The maturity here means the extent of the user’s ability to produce and exchange information. These stages are the milestones, or levels, of collaboration and sharing of information that teams, and organisations aspire to. Defining these milestones is the main purpose of the different BIM maturity models that exist nowadays (Succar et al., 2012). The European Commission (EC) encourages step-by-step maturity models starting from BIM level 0 up to 4, to move the industry from a traditional modelling approach towards an open BIM approach. According to the EC, to reach BIM level 4 “all project, operational documentation and history are linked to objects in the model” (European Commission, 2017).
Due to growing concerns over the environmental, economic, and social impacts of the built environment, BIM is increasingly used to facilitate various sustainability analyses. In this regard, the concept of Green BIM initiated as the systematic digitalisation of building life cycles to accomplish established sustainability goals (Barile et al., 2018; Wong & Zhou, 2015). As such BIM has been integrated with Life Cycle Analysis (LCA), Life Cycle Costing Analysis (LCCA), and recently with Social Life Cycle Analysis (S-LCA) (Llatas et al., 2020). Today several BIM applications perform sustainability analysis in conjunction with Green Building Rating Systems (Sartori et al., 2021). In relation to housing BIM plays a crucial role in addressing affordability and sustainability issues from creation to maintenance, as well as the beyond end-of-life phases. However, many challenges remain for it to be fully and inclusively integrated within the AEC practice and for the full potential of BIM to be realised.
Created on 16-02-2022
Read more ->Area: Design, planning and building
Design for Disassembly (DfD), also referred to as Design for Deconstruction or Construction in Reverse, is the design and planning of the future disassembly of a building, in addition to its assembly (Cruz Rios & Grau, 2019). Disassembly enables the non-destructive recovery of building materials to re-introduce resources back into the supply chain, either for the same function or as a new product. Designing buildings for their future disassembly can reduce both the consumption of new raw materials and the negative environmental impacts associated with the production of new building products, such as embodied carbon. DfD is considered the “ultimate cradle-to-cradle cycle strategy” (Smith, 2010, p.222) that has the potential to maximise the economic value of materials whilst minimising harmful environmental impacts. It is therefore a crucial technical design consideration that supports the transition to a Circular Economy. Additional benefits include increased flexibility and adaptability, optimised maintenance, and retention of heritage (Rios et al., 2015).
DfD is based on design principles such as: standardised and interchangeable components and connections, use of non-composite products, dry construction methods, use of prefabrication, mechanical connections as opposed to glues and wet sealants, designing with safety and accessibility in mind, and documentation of materials and methods for disassembly (Crowther, 2005; Guy & Ciarimboli, 2008; Tingley & Davison, 2011). DfD shares commonality with Industrialised Construction, which often centres around off-site prefabrication. Industrialising the production of housing can therefore be more environmentally sustainable and financially attractive if building parts are produced at scale and pre-designed to be taken apart without destroying connecting parts.
Disassembly plays an important role in the recovery of building materials based on the 3Rs principle (reduce, reuse, recycle) during the maintenance, renovation, relocation and reassembly, and the end-of-life phases of a building. Whilst a building is in use, different elements are expected to be replaced at the end of their service life, which varies depending on its function. For example, the internal layout of a building changes at a different rate to the building services, and the disassembly of these parts would therefore take place at different points in time. Brand’s (1994) Shearing Layers concept incorporates this time aspect by breaking down a building into six layers, separating the “site”, “structure”, “skin” (building envelope), “services”, “space plan”, and “stuff” (furniture) to account for their varying lifespans. DfD enables the removal, replacement, and reuse of materials throughout the service life of a building, extending it use phase for as long as possible. However, there is less guarantee that a building will be disassembled at the end of its service life, rather than destructively demolished and sent to landfill.
Created on 18-10-2023
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Solar Decathlon Competition and LCA | Secondment with UPV
Posted on 27-10-2022
Leading up to the summer I completed my first secondment of three months at the Universitat Politènica de València (UPV), which was conveniently only a three-hour journey south along the Spanish coast from my host institution in Barcelona.
Life in Valencia involved drinking copious amounts of horchata (a local drink made from tiger nuts called Xufa) and enjoying Jardin del Turia, a park that was once a river which today hosts attractions such as gardens, sports facilities, and futuristic cultural buildings designed by architect Santiago Calatrava. I had the pleasure of working with my co-supervisor Ignacio Guillén and Life Cycle Assessment (LCA) expert Alberto Quintana Gallardo, Ph. D. in the department of Applied Physics. Together they provided excellent support with my plans to investigate housing projects from this year’s Solar Decathlon competition and to learn and apply LCA to built case studies during my stay.
As my project investigates Design for Disassembly (DfD) – in addition to Industrialised Construction – the Solar Decathlon competition was an exciting and unique opportunity to observe the disassembly and reassembly of sustainable homes, including the Spanish entry from team Azalea at UPV. As a former practicing architect where I worked with sustainability consultants who normally carry out LCA’s, I was also very eager to learn how to actually do an LCA myself.
Solar Decathlon
So what is the Solar Decathlon competition? It is an international competition where teams from universities build prototype homes known as ‘House Demonstration Units’ (HDU) that showcase the best in innovation and energy efficiency using renewable energy. Although the design aspect of the competition focusses on minimising operational carbon, the build challenge requires teams to first construct their HDU at a site in their home country, disassemble it, then transport and reassemble it in only two weeks at the competition site, also known as the Solar Campus. This means designing for disassembly is integral to the competition, making it a fantastic opportunity to study how housing can be more resource efficient over the building life cycle and understand practical building issues.
The competition and reassembly of the houses took place this year in May at the Solar Campus in Wuppertal, Germany. The 16 teams that made it to the build phase heralded from the Netherlands, France, Sweden, Romania, Czech Republic, Turkey, Taiwan, Germany itself, and of course Spain.
I seized the opportunity to observe and ask questions about the disassembly process, the reassembly process, and carry out interviews with each of the Solar Decathlon teams. When I arrived at UPV at the start of May, Team Azalea from UPV had finished building their HDU called the Escalà project on campus and had just held their inauguration event. Over the first two weeks of my secondment, I visited the house every day whilst it was slowly disappearing as it was taken apart and loaded onto five trucks headed to Germany, where the team would shortly reassemble it all over again! During this time, I got to know the team members who had bonded immensely during the intense competition period until this point. Before heading to Wuppertal myself, I was able to pilot interview questions covering technical and environmental sustainably aspects of the project with the Azalea team, as well as remotely with the SUM team from TU Delft.
The energy at the Solar Campus in Wuppertal was palpable as the teams were busy reassembling their HDU’s, each had an internal floor area of around 70m2 to give an idea of scale. I quickly got to know each of the projects and schedule interviews with the 16 teams, who kindly volunteered their time during the middle of the hectic reassembly period before the houses were judged and opened to the public. I managed to interview 13 teams on-site (the remaining teams were later interviewed online), including participants from different fields and both students and professors. Each team had a unique solution to the brief which called for either vertical and horizontal extensions or in-fill proposals. It was not only insightful but a pleasure speaking with true pioneering experts in housing designed for disassembly. Now’s time to complete the analysis of all that data!
Check out my Instagram highlights of SDE-22 for some on-the-ground footage.
LCA
Life Cycle Assessment (LCA) is an increasingly popular methodology and decision-supporting tool used by industry professionals and scholars to measure and compare the environmental impacts of buildings (European Commission, 2010). An LCA can be used to calculate Whole Life Carbon (WLC), which includes both embodied carbon from all the materials, processes, and transport to construct buildings and the operational carbon produced whilst a building is inhabited. WLC assessments are crucial to set environmental targets to decarbonise our building stock. There is currently a big knowledge gap around LCA amongst architectural practitioners and other stakeholders involved in the delivery of housing, partly due to the time-consuming nature of LCA’s. An LCA can be calculated simply with an excel spreadsheet or using various online platforms and plug-ins such as OneClick LCA, but amongst scholars more heavy software is called for, such as SimaPro – which is was what I would be learning to use whilst at UPV. My aim here was to carry out cradle-to-cradle LCA’s of case studies to quantify the benefits of DfD and the consideration of different lifespans for different parts of the building.
Work began on the first case study of a house designed and delivered by my co-supervisor Ignacio Guillén called Edificación Eco-Eficiente, or ‘EEE’, this was awarded a Class A energy rating and was the first single-family home in Spain to achieve the maximum VERDE* rating of 5 leaves. EEE was built using Industrialised Construction and prefabricated 2D elements that were assembled on-site in only 19 days. I was also able to visit the house on the UPV campus, though due to security reasons it can’t be used as a living-lab, which is a shame as it could provide some great in-use data on energy efficiency!
Using Simapro was (and still is) a steep learning curve with an incredible amount of precise and technical information that needs to be included. Imagine having to enter every single built element manually into a software, and not just modelled 3D objects but also coatings such as the surface area of zinc needed to galvanise steel, the grouting between tiles… the list goes on. Needless to say, LCA is an invaluable tool and will contribute greatly to my doctoral research project.
¡Hasta pronto!
I will be seeing my colleagues in Valencia again next month for the VIBRArch conference held by UPV to present my ongoing work on LCA. My secondment was invaluable in learning new skills and creating connections, particularly through the Solar Decathlon competition that I am continuing to follow up. Thank you to everyone at UPV, the Azalea team, and Solar Decathlon participants who provided such positive experiences and research opportunities!
*VERDE is a sustainability certification developed by Green Building Council Spain
Bibliography
Solar Decathlon Europe Competition website and knowledge platform with previous year’s entries
https://sde21.eu/sde21
https://building-competition.org/
Team Azalea’s Instagram page and website
https://www.instagram.com/azaleaupv/?hl=en
https://www.azaleaupv.com/
London Energy Transformation Initative ‘LETI’ provide an excellent embodied carbon primer for further reading on Whole Life Carbon
https://www.leti.uk/_files/ugd/252d09_8ceffcbcafdb43cf8a19ab9af5073b92.pdf
References
European Commission. (2010). ILCD Handbook - General Guide for Life Cycle Assessment: Detailed Guidance (1st ed.). Publications Office of the European Union.
Secondments
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WasteBuild Zero conference in Amsterdam
Posted on 18-05-2023
During my current secondment in the Netherlands at TU Delft, I attended the two-day WasteBuild Zero conference at the NSDM in Amsterdam, which pushes circularity in the built environment to the forefront. There was so much to unpack after many great presentations and panel discussions with people passionate about sustainability. Speakers included practicing architects, engineers, deconstruction and demolition experts, sustainability experts, economists, and researchers. Here are some of my key takeaways:
Defining circularity: There are inconsistent ways to calculate circularity across industries and stakeholder groups, it still needs to be defined with a series of agreed metrics and measures. Embodied carbon on the other hand has clear metrics, but few countries regulate it*.
Economic incentive: Circular construction and bio-based materials are more expensive; we need to make these solutions more attractive. This can be achieved by shifting taxation from labour to resources. Otherwise, demolition and downcycling are inevitable. In the UK the problem of 20% VAT levy on reuse and refurbishments as opposed to zero on demolition or new-build needs to be fixed.
A lack of timber industry: For designers to responsibly specify mass timber (which also sequesters carbon) that doesn’t incur excessive embodied carbon in transport, countries other than Austria and Scandinavia need their own local timber industries.
Early interdisciplinary engagement: Figuring out solutions and identifying opportunities for material reuse early-on makes it more likely to be cheaper. Demolition teams and contractors have a lot of knowledge and should lead in strategies from the get-go. Furthermore, demolition companies should also provide a disassembly team to minimise destruction and increase reuse.
Flexibility: The design, budget, and scope should have more flexibility and not be fixed to test new methods and products to innovate and challenge the status quo.
Pre-demolition audits: Documenting all existing materials on-site helps them go back into the supply chain, maximise reuse and know-how, and should inform the design process.
Waste classification: Bodies such as the Environmental Agency are preventing the reuse of existing materials on-site such as excavated clay to make earth-blocks and tiles - there were several examples of this presented in case studies.
Procurement: Contractors are not incentivised to incorporate reuse and accept a higher level of risk. Tender documents should also state on the first page the requirement for second-life materials, if it’s on page five it won’t get looked at.
Warranties: We need more protocols and standardisation to speed up the warranty process, otherwise each material must be tested which takes too long and is too expensive. Risk engineers and insurers should be engaged early on. If possible, try to involve the company that originally produced the material/product.
Supply chains: There is a huge gap in the supply chain, lots of materials are available but performance criteria and a lack of warranties prevent reuse. The supply chain should provide a breakdown of materials and as-built information, and should be engaged to take materials back and remanufacture them.
Material passports: These are key at the demolition/disassembly and preparation stage, but there is concern over the level of information needed, it is useful at an element level (products made from few materials) otherwise we could get bogged down with too much data.
It’s tough for construction teams to make sustainable choices when we are living and working in a broken system, where it is currently acceptable to landfill almost absolutely everything and it’s often cheaper and easier to source products from China than to reuse local materials. Architects cannot rely on ‘enlightened clients’ during the continued climate crisis, to quote Hans Hammink from De Architekten Cie, we should rethink the role of the architect as “protector of materials”.
Lastly, the lack of information sharing is holding back more widespread and urgent change, research in industry is usually confidential and money is still the main driver. The transition to a circular economy will require a true sharing economy of both materials and knowledge, and we need to ensure lessons learnt are also looped back into the cycle.
See you next year WasteBuild!
*The Architects Climate Action Network UK are continuing to push forward a bill to regulate embodied carbon: https://www.architectscan.org/embodiedcarbon
Conferences, Secondments
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