Policy guidance on circular construction is unclear
Created on 21-11-2024
Design, planning and building
Stakeholders attempting to deliver circular housing are confronted with unclear, and at times contradictory industry guidance on circular construction from the European Commission down to the local level. This includes variation across the EU-wide framework Level(s), national policies, advice from the Green Building Council (a non-governmental organisation), regional and local guidelines. Built environment professionals and local councils require harmonised and practical guidance that has been applied to exemplary case studies.
Systems knowledge
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Target knowledge
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Transformation Knowledge
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Related cases
APROP | Temporary social housing for people at risk to residential exclusion
Created on 09-10-2024
Innovative aspects of the housing design/building
The APROP design and construction system is based on prefabricated modules, providing dignified and energy efficient dwellings for members of society who have difficulties in accessing housing. The homes achieve an AA Energy Rating, which the Barcelona municipality equates to a level of energy consumption four to six times lower than that of a conventional building of the same characteristics (Ajuntament de Barcelona, 2019a). Circularity is integral to the concept of the project, with upcycled shipping containers forming the structure, which would otherwise be considered as waste and sent to landfill. In terms of time and cost savings, owing to the dry and lightweight structure the entire building can be disassembled in four weeks are reassembled elsewhere, significantly reducing on-site construction time.
APROP has been documented as an exemplary project by the municipality and features in the “Innovation in affordable housing Barcelona” and “Barcelona right to housing” reports (Ajuntament de Barcelona, 2018; Hernández Falagán, 2019). The architectural team includes three practices: Straddle3 and Eulia Arkitektura in the design stage, and Yaiza Terré for the delivery stage. Following the announcement of the Bauhaus award, a prize that aims to demonstrate sustainability in alignment with the European Green Deal (European Commission, 2022), Housing Europe declared APROP “an emerging housing model” (Housing Europe, 2021). The project has also been recognised by various other local and international awards (Ajuntament de Barcelona, 2022). Although APROP is built to the same building standards as conventional housing in Barcelona, it received a critical response from a UK newspaper article (The Guardian, 2019), which raised concerns over the danger of lowering standards in the quality of housing if replicated elsewhere. Re-purposing shipping containers to provide housing has become an established industry in many countries but can typically lead to poor thermal and acoustic performance if it is not done well. This was highlighted in the same article by the principal architect David Juárez from Straddle3, who asserted that "building with containers can bring terrible results unless you really make an effort".
Methodology and research project by ATRI
The APROP programme is the result of research carried out by Tactical Accommodations of Inclusive Repopulation (ATRI), an interdisciplinary team supported by the Barcelona municipality that consists of architects, builders, economists, a lawyer, and a social scientist. The group was initiated in response to a lack of social and emergency housing in the Barcelona region. The project framework was formed between the Department of Social Rights, Cooperativa Lacol (the architects responsible for housing cooperative “La Borda”), Bestraten Hormias Arquitectura, and architectural practice Straddle3. ATRI cite the thesis project of architectural scholar Gerardo Wadel on Industrialised Construction and sustainability as further theoretical grounding for the APROP programme (ATRI, n.d.-a; Wadel, 2009). The methodology crosses disciplines to encompass four key areas: urbanism, architecture, economy, and management. This research culminated into the three main characteristics of an ATRI building: reversibility, being lightweight, and minimising execution time.
Construction characteristics, materials and processes
The prefabricated construction method and modular design strategy are characteristic of Industrialised Construction. Although the project is based on off-site construction, this did not take place in a factory setting and traditional manual labour was used (Ajuntament de Barcelona, 2019b). The prefabricated modules were transported through the narrow inner-city streets and placed on site within a steel frame using a large tonnage crane. The lightweight corrugated steel containers used were “last trip” containers that are easily available in the coastal port city of Barcelona, meaning the amount of embodied carbon to transport the containers was more minimal compared to further inland locations. Shipping containers are based on international ISO standards and are designed to universal sizes and can support their own weight whilst being stackable. Therefore, making changes to the structure to provide openings for doors and windows compromises their structural integrity and requires additional structural support. Considering the need to scale up production of the programme and the need to modify the structure, the construction system could potentially be modified in the future to use steel beams and columns formed from recycled material, rather than reusing steel in the form of shipping containers.
The apartments integrate underfloor heating to provide efficient thermal comfort for residents, whilst the double skin façade ensures the homes do not overheat. The skin includes a translucent outer layer made from cellular polycarbonate and timber to increase natural daylight. This also serves to visually adapt the building to its context and allows the shipping containers beneath to be visible. Knauf products were used to create a double plate system in the ceilings and partitions for a structural 60-minute fire rating. The modules, façade and roof incorporate dismountable dry joints for disassembly, recycling, and to enable the easy relocation of parts or whole buildings if necessary.
Energy performance characteristics
The project team claim APROP housing reduces energy consumption by 25% and greenhouse gas emissions by 54% (European Commission, 2021). The double skin façade, layout, and the use of photovoltaics significantly contributed to the achievement of the AA energy certification. These design decisions were tested during the design process using energy simulation models and collaboration with an energy and resource efficiency consultancy (European Commission, 2021). Energy is supplied by an aerothermal heat pump that extracts energy from the ambient air, which is more energy efficient compared to conventional methods. Passive design strategies are also incorporated with exterior openings positioned to produce cross ventilation and maximise sunlight during the winter and shade in the summer months. These techniques significantly reduce heating and cooling demands and further improve the energy efficiency performance.
Financial benefits
The APROP Gothic pilot project cost €940,000. The reuse of shipping containers is reported to have resulted in a 10% material reduction in construction costs compared to traditional methods, in addition to cost savings from a much shorter project programme. These savings are referred to as the Pre-Manufactured Value (PMV) in relation to Industrialised Construction methods, as outlined in the Farmer report (Farmer & Thornton, 2021). The APROP system offers the possibility of further cost savings if the project is replicated through economies of scale; plans are already underway for multiple APROP projects in the city to provide permanent social housing in additional to temporary housing. Work on the second pilot project, a block of 42 dwellings in El Parc i la Llacuna del Poblenou, began in January 2022.
Solar Decathlon Europe 2022
Created on 21-11-2024
Relationship to urban environment
The SDE 2022 competition called for innovative urban housing solutions within existing contexts, allowing teams to choose from one of three scenarios: (1) a vertical extension adding additional storeys, (2) closing gaps between buildings, or (3) a horizontal extension. Among the sixteen built projects, eleven were top-ups, four were in-fill, and one was a horizontal extension. Some teams opted for a top-up solution for the existing Café Ada site in Wuppertal, whilst others produced solutions tailored to a local context of their home country. Despite the diverse origins of the projects, all of them had to be transported and operated at the Solar Campus in Wuppertal, Germany. Table 1 shows the results of the competition, which was won by team RoofKIT from the Karlsruhe Institute of Technology. Note that the third place was tied between teams SUM from TU Delft and Aura from Grenoble School or Architecture.
Innovative aspects of the housing design/building
As documented in the competition Source Book (Voss & Simon, 2022), the teams developed various innovative biological, low-carbon, and circular materials and products from various other sectors, such as mycelium bound insulation, sea grass, recycled newspapers, jeans for insulation, and recycled yoghurt pots for kitchen and bathroom joinery. Chalmers University’s Team Sweden experimented with 3D printed cellulose whilst team X4S from Biberach University of Applied Sciences used tubular thin film photovoltaics, originally developed for large-scale use in agriculture, as pergola roofing. Innovative layouts included tessellating modules to provide multiple configurations, and highly efficient living units for multiple households (SDE, 2022).
Construction characteristics, materials and processes
All teams used Industrialised Construction (also known as Modern Methods of Construction in the UK) to varying degrees to prefabricate their buildings in their home countries. Construction included timber-based 3D modular and 2D panelised elements, and the competition also required the use of BIM to model the designs. To be able to disassemble and reassemble the HDUs they had to avoid the use of glues and wet sealants and instead join the building parts using various forms of reversible connections. Strategies included interlocking wood jointing, steel plates and footings, tapes, and mechanical joints such as screws, rivets, and bolts (Voss & Simon, 2022). These joining methods were designed to withstand water-ingress as well as airtightness, which was tested using the blower door test.
Energy performance characteristics
High energy efficiency performance and the production of on-site renewable energy were critical design aspects of the competition. All homes were designed to use electricity as the sole energy source for energy services and were powered by air- and ground-source heat pumps, and photovoltaic panels were integrated both horizontally on roofs and vertically on façades, depending on whether the project responded as an infill or top-up solution (Voss & Simon, 2022). Nine HDUs met the Passive House standard and included innovative passive strategies, such as solar chimneys, which were implemented by five teams, including Azalea from the Polytechnic University of València. Eight of the sixteen teams were chosen to remain on-site for an additional 3-5 years after the competition as Living Labs to provide in-use research data (University of Wuppertal, 2022).
Involvement of other stakeholders
The competition incorporates a level of entrepreneurship, with teams encouraged to forge partnerships and gain sponsorship from various industry partners. This provided teams with a mixture of financial support, in-kind services, or donations of materials and products. The extent of collaboration with partners and sponsors varied across the teams: these were formed not only with contractors and product suppliers, but in some cases with housing associations and local municipalities as well. The involvement of stakeholders from different fields not only fostered collaboration between fields, but brought about innovative construction solutions, bridging the gap between academia and industry.
WikiHouse: South Yorkshire Housing Association
Created on 16-10-2024
South Yorkshire Housing Association manages 6,000 homes to provide social and affordable rent housing for over 10,000 residents (SYHA, n.d.). The housing association is helping to lead the way in less conventional construction methods, utilising industrialised construction to deliver a portion of its homes. As a founding member of the Off Site Homes Alliance (OSHA, n.d.), SYHA is also part a framework and network of registered housing providers, local authorities, contractors, and strategic partners, dedicated to delivering high-quality, affordable housing produced using both 2D panelised and 3D volumetric approaches.
The two semi-detached WikiHouses, with an approximate floor area of 70m², are situated in Sheffield, close to the city centre. They were delivered in collaboration with product design providers Open Systems Lab, architects Architecture 00, engineers Momentum, manufacturers Chop Shop, and assembly and installation were carried out by Castle Building Services supported by Mascot Management. The project is not only exemplary in reducing embodied energy in housing but also proves to be energy efficient, having earned runner-up in the Ashden Awards for Energy Innovation.
Design
WikiHouse aims to democratise housing with the creation of standardised and open-source designs incorporating industrialised construction, based on foundational principles such interoperability and a lean approach inspired by the Toyota Production System (WikiHouse, n.d.-a). WikiHouse provided SYHA with a “jigsaw of pieces” in the form of panelised components designed to be assembled around a framing system. The system was made from simple plywood construction, with no need for steel due to the proposed low building height. Timber is not only ideal for buildability and deconstruct-ability as a lightweight material, but it also possesses carbon sequestering properties. It should be noted the open-source product can be limiting for some adopters of WikiHouse as additional design, construction and installation services are not included. SYHA therefore needed to fill the gap between the product and delivery to their end-users.
Manufacturing
WikiHouse products lend themselves to self-build construction or utilisation of ‘micro’ factories. SYHA’s pilot used localised construction to manufacture the plywood frame using digital files, cut by CNC machining company ‘Chop Shop’, located just 1 mile from the site (Plowden, 2020). Cutting the pieces was a fast and efficient process, which was designed to minimise material waste. Chop Shop also assisted by storing the building parts until the site was ready for assembly due to the lack of on-site storage space. WikiHouse seems to be well suited to manufacture by a distributed network of small manufacturers. However, according to SYHA, there is potential for scalability with larger housing association schemes in future. In addition, the production strategy is ideal to unlock small, tricky sites within the housing association’s portfolio, facilitating the production of high-quality housing with high circularity potential.
Transport and assembly
The dimensions of the timber frames were small enough to be delivered to site using a transit van rather than a larger lorry, which proved to be more manageable and cost effective. Once on site, the prefabricated building parts were assembled “like a jigsaw” using a step-by-step manual, although SYHA felt the instructions could be enhanced in the future to improve delivery by a range of stakeholders (Plowden, 2020).
The project programme was much shorter compared to a traditional build, the first home was manufactured and assembled in under a month. This process was even faster for the second home due to the experience gained from the first home, highlighting potential to improve efficiency for larger schemes in the future. As prefabrication and assembly are still unconventional, the transition between these processes may present additional complexity for the stakeholders involved compared to a traditional build.
In the case of SYHA’s WikiHouse, Miranda found “the manufacturer saw its job as providing the cut pieces for the installer to install, they didn't appreciate that they were part of a manufacturing process with the installer”. She went on to highlight that manufacturers and installers are typically separate parties in the UK, with installers often being main contractors who aren’t used to off-site methods. The team also had to overcome issues with unexpected ground conditions which hadn’t been included within the original site survey, though this was unrelated to the construction system used.
Building performance
SYHA’s WikiHouse homes have so far proven to be warm and energy efficient, resulting in low energy bills for residents, owing to the high-level of insulation within the plywood structure and panelling. The building strategy ensures easy maintenance and access during the use phase without disturbing residents. This was achieved by incorporating exterior services coupled with dry construction techniques. As a result of their involvement in the whole process, SYHA is able to effectively manage disassembly for future maintenance and potential adaptations, as their Home Maintenance Team were able to observe how the WikiHouses were assembled.
Legal
Providing the design and detailing are correctly implemented, meeting UK building regulations is not an issue with the WikiHouse system, which claims its products will exceed the requirements of UK building regulations (WikiHouse, n.d.-b). However, it proved more difficult to obtain the building warranty for the SYHA pilot. All new products need to be warranted, which requires warranters to inspect the whole building process to guarantee the necessary requirements are met.
SYHA’s WikiHouse utilised the Buildoffsite Property Assurance Scheme (BOPAS) (n.d.), which is a specialist warranty provider for buildings using industrialised construction, referred to as Modern Method of Construction (MMC) in the UK. Homes with BOPAS accreditation are readily mortgageable for a minimum of 60 years.
Financial
Using an off-site approach can be financially advantageous, as more time is invested upfront to plan, design, and manufacture. This shortens the time spent on-site and therefore reduces preliminary costs for the operation of the construction site. Although the project benefitted from a shortened timeline due to the industrialised approach, the WikiHouse system ultimately proved to be more expensive than a traditional build.
According to Miranda, the cost of the completed homes was approximately 33% higher than a traditional build but she estimates if they were to build using WikiHouse again - taking on-board lessons learnt - the premium would reduce to 12% (Plowden, 2020). However, there is hope for the WikiHouse system to become a more financially competitive alternative to traditional build in the future. For this to happen, Miranda suggests improving efficiency of the assembly process, particularly with faster utility connections. Additional financial viability could also be achieved if the system were to be applied to larger sites. In regard to a life cycle costing approach, Miranda believes it is too early for SYHA to say whether the WikiHouse pilot will prove to be cheaper than a traditional build in the long-term.
Related vocabulary
BIM
Design for Disassembly
Industrialised Construction
Circular Economy
Life Cycle Assessment (LCA)
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
Read more ->Area: Design, planning and building
Industrialised Construction, also referred to as Modern Methods of Construction in the UK (Ministry of Housing, 2019) and Conceptueel Bouwen (Conceptual Building) in the Netherlands (NCB, n.d.), is a broad and dynamic term encompassing innovative techniques and processes that are transforming the construction industry (Lessing, 2006; Smith & Quale, 2017). It is a product-based approach that reinforces continuous improvement, rather than a project-based one, and emphasises the use of standardised components and systems to improve build quality and achieve sustainability goals (Kieran & Timberlake, 2004).
Industrialised Construction can be based on using a kit-of parts and is often likened to a LEGO set, as well as the automotive industry's assembly line and lean production. Industrialisation in the construction sector presents a paradigm shift, driven by advancements in technology (Bock & Linner, 2015). It involves both off-site and on-site processes, with a significant portion occurring in factory-controlled conditions (Andersson & Lessing, 2017). Off-site construction entails the prefabrication of building components manufactured using a combination of two-dimensional (2D), three-dimensional (3D), and hybrid methods, where traditional construction techniques meet cutting-edge technologies such as robotic automation. Industrialised construction is not limited to off-site production, it also encompasses on-site production, including the emerging use of 3D printing or the deployment of temporary or mobile factories. Industrialised Construction increasingly leverages digital and industry 4.0 technologies, such as Building Information Modelling (BIM), Internet of Things, big data, and predictive analysis (Qi et al., 2021). These processes and digital tools enable accurate planning, simulation, and optimisation of construction processes, resulting in enhanced productivity, quality, and resource management. It is important to stress that Industrialised Construction is not only about the physical construction methods, but also the intangible processes involved in the design and delivery of buildings.
Industrialised construction offers several benefits across economic, social, and environmental dimensions. From an economic perspective, it reduces construction time and costs in comparison to traditional methods, while providing safer working conditions and eliminates delays due to adverse weather. By employing standardisation and efficient manufacturing processes, it enables affordable and social housing projects to be delivered in a shorter timeframe through economies of scale (Frandsen, 2017). On the social front, Industrialised Construction can enable mass customisation and customer-centric approaches, to provide more flexible solutions while maintaining economic feasibility (Piller, 2004). From an environmental standpoint, industrialised construction minimises waste generation during production by optimising material usage and facilitates the incorporation of Design for Disassembly (Crowther, 2005) and the potential reusability of building elements, promoting both flexibility and a Circular Economy (EC, 2020). This capability aligns with the principles of cradle-to-cradle design, wherein materials and components are continuously repurposed to reduce resource depletion and waste accumulation.
Challenges remain in terms of overcoming misconceptions and gaining social acceptance, the slow digital transformation of the construction industry, high factory set-up costs, the lack of interdisciplinary integration of stakeholders from the initial stages, and adapting to unconventional workflows. However, Industrialised Construction will undoubtedly shape the future of the built environment, providing solutions for the increasing demand for sustainable and affordable housing (Bertram et al., 2019).
Created on 09-11-2023
Read more ->Area: Design, planning and building
Circular Economy (CE), also referred to as circularity, is a sustainability concept applied to various industries – including the built environment – which aims to improve the way products are made and consumed, and essentially to prevent the unnecessary destruction of resources. The CE idea is founded on the rejection of the current take-make-waste model and instead supports a system that is “restorative or regenerative by intention and design” (EMF, 2013, p.7). The European Commission defines CE as “a system which maintains the value of products, materials and resources in the economy for as long as possible and minimises the generation of waste” (EUR-Lex, 2021). CE builds upon concepts such as Cradle-to-Cradle (McDonough & Braungart, 2002) and The Performance Economy (Stahel, 2010). The term has recently grown in popularity, as evidenced in a study by Kirchherr et al., who identified 221 CE definitions, though the meaning of the term remains largely ambiguous (2023).
CE encompasses both design and business considerations to better ensure products are responsibly managed and retained at their highest value possible within the value chain, rather than being destroyed. Business strategies include shifting consumption from selling products to services; this can take the form of Product-as-as-Service models or take-back schemes (Tukker, 2015). Several prominent theoretical frameworks support the CE transition, these include the R-Ladder outlining a decision-making hierarchy (Potting et al., 2017), the Ellen MacArthur Foundation’s Butterfly diagram which distinguishes technological materials from biological materials (EMF, 2013), and Bocken et al.’s four strategies defining the need to close, slow, narrow, and regenerate resource loops (2016). Key circular construction approaches that facilitate circularity in a systematic way include design for disassembly and industrialised construction.
Several political instruments under the European Green Deal promote the progression towards a circular economy in buildings and housing, most notably the Circular Economy Action Plan (European Commission, 2020) and the Waste Framework Directive (EC, 2008). Despite these initiatives and the potential for the CE transition to improve both the environmental sustainability and affordability of housing, it is still in the early stages in Europe. This is largely due to building complexity, short-term financial barriers, and the persistence of common practices such as the extraction of raw materials and building demolition. However, several practical advancements that have been implemented include Circular Economy Statements within the London Plan (GLA, 2022), the Building Circularity Indicator (BCI) in the Netherlands (Alba Concepts, n.d.), and the Building Circularity Tool by OneClick LCA (n.d.).
Created on 30-09-2024
Read more ->Area: Design, planning and building
Life Cycle Assessment (LCA) is a standardised method to comprehensively quantify environmental impacts caused by the production of goods and services, which can be used to inform decision-making in building design. Measurable indicators include Global Warming Potential (GWP), acidification, eutrophication, and water use to name a few (European Commission, 2010). LCA can be used to account for all input and output flows related to the entire building life cycle, from raw material acquisition, manufacture, use and maintenance (e.g. while the building is occupied), to the deconstruction and beyond End-of-Life phase (Sartori et al., 2021).
Calculating an LCA requires information for building products and processes usually found in the Bill of Quantities, which includes the type of material and its density combined with the amount of material, measured in either volume or area. The European standard EN 15978 (2011) provides guidance for the calculation method, which breaks down the life cycle into phases A to D, these are: A Production and Construction, B Use, C End-of-Life, and D Beyond End-of-Life. It should be noted however, that it is difficult to compare different buildings using LCA, as methodologies and assumptions vary, impacting results (Ramboll, 2023). An LCA that includes stage D is known as a ‘cradle-to-cradle’ assessment, this supports a circular approach and considers scenarios relating to the building after its ‘useful service life’. It is crucial for stakeholders to consider the beyond End-of-Life impacts when planning and designing housing to support the circular economy transition, primarily through promoting future material reuse.
LCA is an increasingly relevant component of sustainability assessments for buildings following demand for transparency from the construction industry and trends in performance-based design (Sartori et al., 2021). The LCA method has been incorporated into the European Level(s) framework (Dodd & Donatello, 2020), and BREEAM and LEED assessments. The European Commission advocates for LCA, describing it as the "best framework for assessing the potential environmental impacts of products" (European Commission, n.d.). LCA therefore plays an increasingly prominent role in supporting EU policy and meeting the ambitions of the European Green Deal and related initiatives, such as the Circular Economy Action Plan (European Commission, 2020). At the national level, several European countries utilise LCA to regulate embodied carbon, with other countries expected to follow suit in the coming years (Röck et al., 2022).
Created on 30-09-2024
Read more ->Blogposts
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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