a) Design philosophy According to the Housing Design Awards, the design of the North Wingfield project took a contemporary design approach, combining the features of local vernacular architecture - as adopted from local farms - with the developer's vision and requirements for flexible, sustainable and innovative housing (HDA, 2021). The architectural office DK -Architects explains that this fusion is represented by massing the morphology of the project, traditional architectural elements (e.g. Dreadnought brick (roof), Janinhoff brick (walls)) with modern elements such as large glazing and aluminium cladding. This combination of materials not only provides an aesthetically pleasing appearance, but also helps to capture heat, ultimately reducing heating energy consumption for at least seven months of the year (DK-A, 2021). In addition, several innovative features have been adapted, including the well-planned use of space and the clear conceptual plans that extends beyond the interior spaces to the shared courtyard, which serves as a social gathering place for the tenants. The inspiration for the courtyard was derived from the local identity, the farmstead and the crew yard (HDA, 2021). At the same time, the use of a see-through fence, which extends the sightline into the rural surroundings, provides a calming splash of green colour in each residential unit. The semi-raised upper massing extends the courtyard and provides a semi-enclosed space that enhances the feeling of safety and security (DK-A, 2021). Meanwhile, the buildings in the front row clearly stand out from the surrounding buildings through the use of colours and materials and also serve as an entrance gate to the project (DK-A, 2021; HDA, 2021). Each dwelling has its own mini agricultural space, which has proven valuable for the well-being of the residents. b) Construction process The skeleton of the building utilises an off-site timber frame method of construction, adopting a semi-modular design principle (Davies & Jokiniemi, 2008). This construction method provides a structure with a superior thermal envelope that requires minimal maintenance and is a 'fit-and-forget' solution for the lifetime of the building. In addition, both labour and material costs were significantly reduced due to less reliance on craftsmanship and multiple suppliers. This is in line with the UK government plans to revamp construction regulations to encourage bold, creative and sustainable construction methods (Davies & Jokiniemi, 2008; Sterjova, 2017). The construction process started with ground treatment, followed by the casting of the foundations on site. Meanwhile, the timber frames were manufactured off-site at the supplier's factory, which helped to reduce construction work and thus carbon emissions. The frames were then transported to the site for fixing and external treatment, and all the construction work ran in parallel (Wheatley, 2020). The overall process can be seen in Figure 1. c) Sustainability integration At the sustainability level, the project worked on several areas to maximise the adaptation of sustainability features and minimise the impact on the natural environment (HDA, 2021). Creating sustainable buildings Through sustainable design and layout (e.g. orientation, maximising daylight, optimising solar gain). Creating high quality outdoor environments (e.g. public and private open spaces that provide shade and shelter and consider flood retention and multi-functional green spaces to protect wildlife). Use of sustainable water management techniques (e.g. use of sustainable drainage systems and consideration of surface water run-off). Use of sustainable waste management facilities for private and communal use (through the appropriate provision of waste and recycling bins). Focus on reducing the use of non-renewable energy. Reduction of carbon emissions The project has been designed in accordance with the highest level of building regulations and sustainability standards, in line with the Government's 10-year timetable for all new homes to be carbon neutral by 2016. Water recycling techniques (such as grey water and rainwater harvesting). Sustainable Transport (reducing reliance on the private car, incorporating practical and accessible sustainable transport patterns). d) Energy performance One of the tools to assess building energy efficiency in the  UK is the Energy Performance Certificate (EPC), which is defined by the Department for Levelling Up, Housing and Communities as: A rating scheme that summarises the energy efficiency of buildings; it includes a certificate that gives a property an energy efficiency rating from A (most efficient) to G (least efficient) and is valid for 10 years (DLUHC, 2014). The EPC is produced using the Standard Assessment Procedure (SAP), which is defined by the Department for Business, Energy & Industrial Strategy as follows: The method used to assess and compare the energy and environmental performance of properties in the UK [...] it uses detailed information about the property's construction to calculate energy performance (DBEIS, 2013). The North Wingfield project has successfully achieved a (B) rating - equivalent to 84 out of a maximum possible 100 points with a high potential for an (A) rating equivalent to 95 points (DLUHC, 2021). This score is the result of The use of high-performance materials with very good thermal transmittance properties (walls: 0.20 W/m²K, roof: 0.11 W/m²K, floor: 0.09 W/m²K). Well-designed ventilation system that achieves a good air tightness indicator (air permeability 4.9 m³/h.m²). Low consumption of primary energy of 94 kWh/m2. Another indicator is the Environmental Impact Score (EIS), which shows the impact of a building on the environment through the estimated carbon dioxide (CO2) emissions calculated at the time of the EPC assessment (DLUHC, 2014). The higher the score, the lower the building's impact on the environment: like EPC labels, the environmental impact score is graded from A to G (DBEIS, 2014). The project generates 1.4 tonnes of CO2 annually. This is less than a quarter of the 6 tonnes emitted by an average household. By improving the EIS rating to A, CO2 production will be reduced to 0.3 tonnes, which will distinguish the project as one of the most environmentally friendly projects (DLUHC, 2021). Figure 2 shows the EPC and EIS breakdowns of the properties.

The review and the analysis of this case is based on several sources of data including project design statements and reports (e.g., planning, architectural, transport, drainage, heritage, landscape, tenure, sustainability and energy), design drawings, planning application and the associated documentation, and archival records obtained from the designers and the East Suffolk planning portal. As well as conducting interviews with the actors involved in the project planning and design, namely the architects, energy system designers and sustainability specialists. Therefore, this review is structured to address various key aspects such as, design, construction, sustainability, community impact and cultural heritage. 1- Design statement “The initial idea was a cricket pitch on the existing playing field and on the leftover land to develop 25 to 30 housing units. We saw an opportunity to connect the dots by connecting the school site into the cricket field and create better spaces and connectivity for the neighbouring communities […] through prober massing the site was optimised to increase the density to 61 housing units, maximising the views towards the park and generate best returns for the council […] that and investing in East Suffolk Council affordable housing scheme” (M. Jamieson, personal communication, June 13, 2023). The Deben Fields development is located near the centre of Felixstowe in Suffolk, England (Figure 1). The site was previously occupied by Deben High School, which was built in 1930, surrounded by low-density semi-detached housing. In their design statement, TateHindle, the architects responsible for the project, articulate a design philosophy centred around the creation of an environmentally, socially, and economically sustainable neighbourhood. This vision places paramount importance on people, their lived experiences, and the integration of nature into the living environment (TateHindle, 2021, 2022). The site's redevelopment aligns seamlessly with East Suffolk Council's Housing Strategy, which emphasises the expansion of council-owned affordable housing through innovative and sustainable methods. To adhere to this strategy, the architect chose to preserve and repurpose existing structures on the site, including the school hall and its annexes. These buildings were meticulously retained, redesigned, and refurbished to serve as a new indoor public facility catering for both the current and anticipated population (ESC, 2021). The project site is 3.89 hectares, of which 2.65 hectares is open green space (cricket pitch and park) and 1.36 hectares is allocated to residential development, with a net density of 53 dwellings per hectare and a total of 93 car parking spaces (61 for residential and 32 for leisure and community services) and 163 cycle spaces (HDA, 2022; TateHindle, 2021). The project is designed according to Passivhaus standards with airtight building envelopes and comprises 61 dwellings with 18 one-bedroom, 28 two-bedroom, seven three-bedroom and eight four-bedroom, spread across semi-detached houses, flats and maisonettes. From a tenure distribution point of view, 68 per cent are available at affordable rents, while the remaining 32 per cent are intended for open market sale (TateHindle, 2021). The average floor area of the housing units is 74.0 m², five per cent above the floor area requirement described by the Nationally Described Space Standard (HDA, 2022). In terms of ownership, however, the aim is to deliver a ‘tenure neutral’ project, so there is no physical distinction between open-market, shared ownership and affordable rental housing. The tenure mix has been integrated throughout the site to ensure that the project delivers proper housing that meets the needs of the housing market. Figure 2 illustrates Deben Fields tenure distribution and housing typologies plans. 2- Construction TateHindle's structural design statement outlines their goal of achieving a highly insulated façade construction. This was accomplished through the implementation of load-bearing double stud timber frame walls and load-bearing timber metal web beams at both floor and roof levels. The project uses Typical Passivhaus Foundations (TPFs) to minimise thermal bridging and achieve low U-values for the ground slab construction. Cradden (2019), however, explains that there are multiple challenges when using TPFs, such as soil conditions, material and geological properties (Cradden, 2019). To address these challenges, a shallow foundation method was chosen within the Red Crag Formation, a geological structure in south-eastern Suffolk defined by a basal pebble bed overlaid with coarse shell sand. This approach utilised the mini-pile technique, thereby bypassing the need for extensive and deeper excavations. In addition, Modern Methods of Construction (MMC) are used to maximise the use of off-site construction and achieve high levels of quality through factory-controlled assembly, reduce construction time, minimise noise pollution and construction waste, and reduce CO2 emissions (TateHindle, 2021). 3- Sustainability and energy “The project has similar challenges to others […] with this project electrification and overheating were the main challenge […] so we did really want to simplify the forms to make it more Passivhaus compliant and cost-effective […] We started from rectangles; obviously you can then add and remove to create interest and increase efficiency” (sustainable design specialist, personal communication, July 20, 2023). To achieve the planned outcomes of the economically, socially and environmentally sustainable neighbourhood, Deben Fields has set comprehensive objectives including: improving the well-being of residents, promoting pedestrian and child-friendly design, integrating passive design principles such as natural ventilation and daylighting, optimising construction costs and minimising waste through recycling and efficient use of materials, implementing monitoring systems for seamless building management, reducing sequestered carbon by reusing existing structures, promoting affordability as an overarching principle, adopting a fabric-first approach to reduce energy consumption and tackle fuel poverty, addressing future sustainability requirements, using renewable energy through photovoltaics to power communal areas and providing spaces that encourage social interaction such as areas for growing food and for play. To translate design objectives into a practical design language, the project employed various approaches, as explained in the following subsections. 3.1- Architectural design and technology integration The primary emphasis is placed on optimising the orientation of the buildings to harness passive solar gain effectively, thereby ensuring ample natural lighting and thermal comfort within indoor spaces (Figure 3). In pursuit of energy efficiency and to reduce overheating impacts, a simplified building form was devised. This involved implementing measures to minimise thermal bridging and establish an airtight building envelope, thereby reducing undesired energy losses. To emphasise the importance of insulation, sufficient provisions were made in the walls to allow for higher levels of thermal protection. A mechanical background ventilation with heat recovery system (MVHR) was used to create a well-ventilated and comfortable living environment. Furthermore, strategically positioned openings, balconies, entrances, sunshades, and shade pergolas contribute to a cohesive architectural language, fostering socially stimulating spaces while adhering to energy-efficient design principles in line with Passivhaus standards. The high-performance triple glazed windows have been carefully positioned and sized to allow natural cross ventilation. All of such techniques maximise control over the building envelope and reduce energy consumption. 3.2- Policy and standards To achieve the desired sustainability goals, a combination of mandatory and voluntary policies and standards were introduced as part of the project design strategy. Firstly, the mandatory building regulations on sustainability, particularly Part L, which sets specific requirements for insulation, heating systems, ventilation and fuel consumption and aims to reduce carbon emissions by 31 per cent compared to the previous regulations. Secondly, the 'SCLP9.2' – a local planning initiative produced by East Suffolk Council to foment sustainable construction. The SCLP9.2 aims to achieve higher energy efficiency standards resulting in a 20 per cent reduction in CO2 emissions below the target CO2 emission rate, design the dwelling to use less than 110 litres of water per person per day, and encourage the use of locally sourced materials, with a focus on recycling and waste reduction (ESC, 2020, p. 9). Thirdly, the project adhered to Passivhaus standards and set a higher target by meeting higher sustainability standards in terms of energy efficiency, water consumption and material use. CGB Consultants – the sustainability specialist – clarified that with such combination of policies and standards, the dwellings could comfortably exceed the planning target for a 20 per cent improvement over building regulations, as simulated using calculations based on the Standard Assessment Procedure (SAP) (CGB, 2021). 4- Community and cultural heritage In the early design phase, the design team developed a comprehensive communication plan that included public hearings and consultations with the community to inform planners of local needs, foster effective communication with project neighbours and obtain their feedback. However, the restriction of COVID-19 posed a challenge to the effective implementation of the original plan.  In response, the architect and the City Council took alternative measures such as formal online consultations, monthly newsletters, social media updates, a website, public exhibitions, public notices, press releases, emails and letters. As a result, the project received critical feedback and concerns around impacts on nature, traffic, existing buildings, privacy, green spaces and alternative renewable energy sources. Responding to the concerns raised, the project team developed a cycling and pedestrian strategy that introduces the concept of “green corridors", “rain gardens" and “play streets", while carefully allocated parking in line with the National Transport Strategy provides a green roof with photovoltaic panels. The community gardens, use the building structure as a privacy screen and integrate existing culture and heritage into the project (Figure 4). Although the former Deben High School site is not nationally recognised as a historically significant building, it has become a local landmark with local significance and considerable architectural and historical value. Designed by Cecil George Stillman (1894–1968), a British architect known as a "pioneer of prefabrication" (Hinchcliffe, 2004). The proposed architectural language therefore draws on the existing buildings, particularly the school's building and assembly hall, which is considered the largest historic building on the site. The proposed pedestrian corridors also have helped to make the building more visible and put the assembly hall at the centre of the project (TateHindle, 2021). 5- Final reflections This section highlights both the successful aspects and the potential areas for improvement arising from the review in the previous sections. This is by addressing the following questions: What methodologies were deployed within Deben Field that can be classified as exemplifying ‘good' practise? The proposed designs have looked beyond the initial requirements and original goals and proposed economically, socially and environmentally viable strategies and solutions. Jon Bootland (2011) explains that responsible housing design must adopt a rigorous design standard for low energy consumption, develop high-quality and affordable outcomes, and prioritise user comfort (Bootland, 2011). In response, the project has embraced higher design standards that go beyond mandatory building regulations and systematically addressed the challenges of engaging specialist services (including Passivhaus designers, ecology and biodiversity consultants, sustainable drainage designers and sustainability consultants) with a high level of expertise to provide the necessary technical feedback. In addition, current challenges such as electrification and overheating were proactively addressed by choosing simple architectural forms and integrating renewable energy sources. While the project initially took a top-down approach, the community was actively involved in the early design phases through a variety of well-organised communication channels (as listed in section 5.4). The project team ensured that responses to planning notices were reviewed, analysed and incorporated into the architectural language of the project. For example, when neighbours raised privacy concerns, the building massing and layout were adjusted to form a privacy screen without compromising the number of dwellings provided. The project has also demonstrated an inclusive design approach that appeals to users of all ages (e.g., community garden and play street). In addition, the design has maximised the benefits of using brownfield sites and seamlessly integrated the existing infrastructure into the project layout, carefully considering the recycling and reuse of materials. What are the vulnerabilities associated with Deben Fields? Knox (2015) stated that the high construction costs of ‘green building’ are a common misconception for which there are insufficient studies (Knox, 2015). However, the study by Chegut et al. (2019) shows that “BREEAM – Excellent” certified buildings are 40 to 150 per cent more expensive to build and attributes these higher costs to specialised design costs, material selection, specialised labour and construction time (Chegut, Eichholtz, & Kok, 2019). The Deben Fields project adopted several sustainability features, such as special materials, green roofs and photovoltaic cells. However, it appears that the project has not conducted a thorough life-cycle cost analysis to determine the costs and benefits of these features and whether additional features are needed in the future. Meanwhile, at the design level and to achieve the intended outcomes, the project complied with several standards and building codes, resulting in a complex and intertwined design structure that makes it difficult to apply the same strategies to other projects. From a sustainable urbanism perspective, density and diverse land use are often considered effective strategies for sustainable development (Carmona, 2021). Despite its central location, the project did not consider density and diversity of land use as a key strategy for its development. For example, the proposed project does not include any retail or commercial uses, and the nearest commercial services are 500 metres from the project (Figure 5). The Deben Fields project is widely regarded as an example of ‘good practice’ in its field, as reflected in the number of awards it has won. However, in order to accurately assess the results of the project, it is essential to conduct additional post-occupancy studies. These studies will allow for a thorough evaluation of the project's features and provide valuable insights and potential areas for improvement. Another major factor contributing to its prominence is the use of numerous well-designed features. These features have improved the overall performance of the project and highlighted the novel techniques (e.g. play street, environmentally friendly materials, reducing overheating through massing). Therefore, it is crucial to undertake comprehensive documentation of all phases, steps and procedures taken during the design and construction of the project. Acknowledgement I would like to express my sincere gratitude to TateHindle Architects for generously providing the necessary data and information for Deben Fields. Special thanks go to Mike Jamieson for dedicating his time and expertise to discussing the project in detail. Additionally, I extend my appreciation to the anonymous interviewees who provided valuable insights into this case. Thank you all for your support and cooperation.

A response to environmental and economic challenges The initiators of Patch22, architect Tom Frantzen and building manager Claus Oussoren, aimed at achieving together what they couldn’t manage in previous commissions independently: an oversized wooden structure characterised by flexibility, distinctive architecture, and a strong commitment to sustainability. They established the development company Lemniskade Projects to pursue their goals (Frantzen et al architecten, 2017). Winning the Amsterdam Buiksloterham Sustainability tender in 2009, Patch22 was not only recognised for its exceptional sustainability scores but also for its innovative circular design approach and its capability to adapt to unforeseen future uses. The project's primary objectives were rooted in environmental sustainability, employing renewable and reusable materials, particularly wood for the main structure and facade. Embracing Open Building principles, Patch22 sought maximum flexibility in dwelling sizes and layouts, offering an ingenious response to the environmental and economic challenges outlined in the tender (Kendall, 2021). The 30-meter-tall wooden structure currently hosts 33 dwellings with diverse sizes ranging from 40 m² to 204 m². The building promotes long-term adaptability, as it is prepared to be easily subdivided into six independent office floors or a maximum of 48 apartments (Frantzen, 2023). This showcases how a single support structure can serve multiple generations, accommodating the dynamic needs of its users while addressing some of the current environmental challenges such as material waste, the construction industry’s carbon footprint or the implementation of design for disassembly practices.     A flexible and adaptable building A flexibility of a building can be enhanced when traditional architectural elements are reassessed. Various strategies were employed to maximize the adaptability of use, layout design, and apartment sizes: No load-bearing division walls The timber laminated post and beam structure, in combination with lightweight division walls, became crucial to ensure size variations between apartments and a greater freedom of choice in defining the layouts. Additionally, by superimposing the residential and office regulations, introducing a generous floor height of 4 m, and structurally supporting floor loads of 4 KN, the building accommodates the potential for entirely or partially utilising residential spaces for office purposes (Frantzen et al architecten, 2017). No vertical shafts inside the apartment In conventional housing, meter cabinets, kitchens, and bathrooms have typically been constructed near vertical shafts to minimise the length of the drains. When developing Patch22, it was unknown which units would merge to form a single apartment, making it challenging to position the vertical shafts. Two shafts were integrated into the structural core, with pre-installed drains, water and electricity conduits running up to each front door, from where they could be extended to the desired location in an apartment (Council on Open Building, 2023). Hollow floors to run services horizontally Patch22 adopts a horizontal services distribution, a common practice in office buildings. The necessary inclination of a toilet drain from the central shaft to the outermost corner of the building results in a floor build-up increase to 50cm. This available space for conduits enables the placement of kitchens and bathrooms anywhere within the dwelling. This departure from the traditional clustering of humid spaces in residential buildings facilitates the creation of multiple floor layouts that respond to the users’ needs. No meters inside the apartment By relocating the heavily regulated meters and main switches to the ground floor and placing the non-regulated secondary fuse boxes at each level, Patch22 provides open spaces which can be subdivided in multiple ways (Frantzen, 2023). The independence of the meters from the dwellings streamlines future adaptations with minimal disruptions to the individual living spaces. Smaller subdivision of legal entities From a technical perspective, designing a flexible and adaptable building is feasible. But it is also necessary to provide the legal mechanisms that make it possible. In the case of Patch22, each floor contains 8 legal units that can be combined horizontally or vertically (Frantzen, 2023). Although, in its current state, most floors have 3-6 dwellings per flight, these legal units could be divided or merged, sold, or rented independently, used as office or as residential spaces. Designing for the unknown Embracing the philosophy advocated by Habraken (OpenBuilding.co, 2023), Patch22 prioritises designing for the unknown. Strategies include over-dimensioning the structure, simultaneous compliance with diverse regulations for different uses, incorporating extra entrance doors, and providing space for additional mailboxes. These approaches keep the design open for future changes, ensuring long-term adaptability.     A sustainable proposal Patch22 embodies sustainability across multiple dimensions.  Environmentally, the building achieves sustainability through a series of strategies: improving energy efficiency, using renewable materials, and fostering layout flexibility. The 2009 design garnered a GPR score of 8.9 and an EPC of 0.2, showcasing its commitment to sustainable practices. The roof, covered with photovoltaic panels, makes the building energy-neutral, while the rainwater collection feeds into a grey water system. The adoption of CO2-neutral pellet stoves, utilising compressed waste wood as fuel, further underlines Patch22’s commitment to eco-friendly energy sources (Frantzen et al architecten, 2017). Despite the challenges posed by fire and acoustic regulations, the building boldly features wood as its main material, with additional thickness added to columns and beams to comply with safety standards. This decision, although increasing costs, remains more economical than the alternative solution of building with 2D CLT panels (Frantzen, 2023). Additionally, the emphasis on long-term layout flexibility aligns with environmental sustainability by reducing waste during future adaptations and facilitating component disassembly. From a social standpoint, involving residents in the design process fostered diversity and strengthened the sense of belonging. Finally, the economic sustainability of Patch22 is evident in its adaptable support, serving as a long-term investment that evolves with changing needs, potentially acquiring different uses over time, benefitting both the planet and the economic interests of its users. Construction characteristics The support components, encompassing the structure, façade, and core of Patch22, are highly prefabricated, facilitating a swift and precise assembly process on-site while minimising waste and reducing disruptions. The structure incorporates over-dimensioned laminated wooden beams and columns, along with vertical core constructed with prefabricated concrete panels (Open Building NOW!, 2020). The NW and SE façades employ CLT panels with a thickness of 220mm, while the NE and SW orientations, serving as the main facades, create loggias on both sides. The loggia's interior façade features modulated sliding doors with CLT prefabricated frames, allowing for the free placement of interior partitions by strategically positioning mullions every 3 meters (Frantzen, 2023). Externally, the loggia is characterised by redwood truss beams with bolted connections to steel joints which facilitate their future disassembly. These buffer zones can be fully enclosed with glazed modular panels in winter or left open with a fixed handrail during the summer. The floor plays a pivotal role in leveraging the flexibility of the apartments within the structure. Employing a Slimline structural flooring system made of IPE 400 steel profiles and a 70mm reinforced concrete slab below, this design allows services to run efficiently within the hollow floor, reaching even the most remote corners of each apartment. After installing drains and other facilities, the floor is topped with an acoustic membrane, a Lewis profile sheet, and 8cm of anhydrite screed with underfloor heating. While initially considering demountable top floor tiles, this solution was deemed complex and expensive compared to the anhydrite screed, which proved more cost-effective and flexible (Frantzen, 2023). By planning in advance for the placement of maintenance registration points to the floor cavity, it was possible to enable access for the necessary alterations while maintaining practicality and affordability.    User customisation process The customisation process at Patch22 began with a search for prospective residents through social media, leveraging it as a platform to connect with individuals interested in actively designing their living spaces in collaboration. Once on board, residents were presented with the opportunity to shape their homes within an entirely empty interior. A catalogue of multiple variations was offered by the architects, allowing some residents to select a pre-designed option that suited their preferences. Alternatively, others opted for a more collaborative approach, working closely with Frantzen architects to create a custom layout. Some residents took an independent venue, either designing their dwellings themselves or hiring another architect to develop their interiors (Frantzen, 2023). Throughout the process, Frantzen provided comprehensive guidance on the technical requirements, ensuring compliance with fire and soundproofing regulations. Residents could choose to have the base installations in the floor installed by the main contractor or to receive the bare shell and install them themselves. This inclusive approach allowed residents to actively contribute to the unique character of Patch22 while ensuring the resiliency of the building support for future generations.

Over the last decades, ESG debt issuance, through green, social or sustainability-linked loans and bonds has become increasingly common. Financial markets have hailed the adoption of ESG indicators as a tool to align capital investments with environmental and social goals, such as the decarbonisation of the social housing stock. According to the Climate Bonds Initiative (CBI), the green debt market has experienced a 50% growth over the last five years (CBI, 2021). However, the lack of clearly established indicators and objectives has tainted the growth of green finance with a series of high-level scandals and accusations of green-washing, unjustified claims of a company’s green credentials. For example, a fraud investigation by German prosecutors into Deutsche Bank’s asset manager, DWS, has found that ESG factors were not taken into account in a large number of investments despite this being stated in the fund’s prospectus (Reuters, 2022). To curb greenwashing and improve transparency and accountability in green investments, the EU has embarked on an ambitious legislative agenda. This includes the first classification of environmentally sustainable economic activities: the EU Green Taxonomy (Regulation 2020/852). The Taxonomy is directly linked to the European Commission’s decarbonisation strategy, the Renovation Wave (COM (2020) 662), which relies on a combination of private and public finance to secure the investment needed for the decarbonisation of social housing. Energy efficiency targets have become increasingly stringent as the Energy Performance of Buildings Directive (EPBD) and its successive recasts (COM(2021)) have been incorporated into national legislation; see for example the French Loi Climate et Resilience (2021-1104, 2021). Consequently, capital expenses for SHOs are set to increase considerably. For example, in the Netherlands, according to a Housing Europe (2020) report, attaining the 2035 energy efficiency targets set by the Dutch government will cost €116bn. Sustainable finance legislation constitutes an expansion of the financial measures implemented by the EU in recent decades to incentivise energy efficiency standards as well as renovations in the built environment. For more detail on prior EU policies, see Economidou et al. (2020) and Bertoldi et al. (2021). The increased connections between finance and energy performance raise specific questions regarding SHOs’ access to capital markets in light of the shift toward ESG. The rapidly expanding finance literature on green bonds draws from econometric models to explore the links between investors’ preferences and yields (Fama & French, 2007). This body of literature on asset pricing relies on the introduction of non-pecuniary preferences in investors’ utility functions together with returns and risks to explain fluctuations in the equilibrium price of capital. Drawing from a comparison between green and conventional bonds, Hachenberg and Schiereck (2018) find evidence of the former being priced at a premium. Similarly, Zerbib (2019) also shows a low but significant negative yield premium for green bonds resulting from both investors’ environmental preferences and lower risk levels. The European Commission’s Joint Research Centre (Fatica & Panzica, 2021) documents the dependency of premiums on the issuer with significant estimates for supranational institutions and corporations, but not for financial institutions. While these econometric approaches offer relevant insight into the pricing of green bonds and the incentives for issuers and investors, they do not account for the institutional particularities of social housing, a highly regulated sector usually covered by varying forms of state guarantees and subsidisation (Lawson, 2013). ESG-labelled debt instruments & Related Legislation Throughout the last two decades, the term ESG finance has evolved to include a large number of financial vehicles of which green bonds have become the most popular (Cortellini & Panetta, 2021). In the social housing sector, ESG comprises a broad array of tools from sustainability-linked loans to less conventional forms of finance such as carbon credits. When it comes to bonds, there is a wide variation in the sustainability credentials among the different types. Broadly speaking, green and social bonds are issued under specific ‘use of proceeds’, which means the funds raised must be used to finance projects producing clear environmental or social benefits. The issuance of these types of bonds requires a sustainable finance framework, which is usually assessed by a third party emitting an opinion on its robustness. Sustainability-linked bonds (SLBs) are an alternative to ‘use of proceeds’. Funds raised in this manner are not earmarked for sustainable projects, but can be used for general purposes. SLBs are linked to the attainment of certain company-wide Key Performance Indicators (KPIs), for example an average Energy Performance Certificate (EPC) rating of “C” in an SHO’s housing stock. These indicators and objectives usually result in a price premium for Sustainable Bonds, or a rebate in interest rates in the case of SLBs or sustainability-linked loans (SLLs) (Cortellini & Panetta, 2021). While there are international standards for the categorisation of green projects such as the Green Bond Principle or the Climate Bonds Strategy, strict adherence is optional and there are few legally-binding requirements resulting in a large divergence in reporting practices and external auditing. To solve these issues and prevent greenwashing, the EU has been the first regulator to embark on the formulation of a legal framework for green finance through a series of acts targeting the labelling of economic activities, investors, corporations and financial vehicles. First, the EU Green Taxonomy (Regulation (EU) 2020/852) is the cornerstone of this new legislation since it classifies economic activities attending to their alignment with the objectives set in the European Green Deal (EGD). When it comes to housing, the EU Taxonomy requires specific energy efficiency levels for a project to be deemed ‘taxonomy aligned’. Second, the Sustainable Finance Disclosure Regulation (SFDR) (Regulation (EU) 2019/2088) mandates ESG reporting on funds, which tend to consist of exchange-traded collections of real assets, bonds or stocks. Funds are required to self-classify under article 6 with no sustainability scope, ‘light green’ article 8 which incorporates some sustainability elements, and article 9 ‘dark green’ for funds only investing in sustainability objectives. Under the SFDR, which came into effect in January 2023, fund managers are required to report the proportion of energy inefficient real estate assets as calculated by a specific formula taking into account the proportion of ‘nearly zero-energy building’, ‘primary energy demand’ and ‘energy performance certificate’ (Conrads, 2022). Third, the Corporate Sustainability Reporting Directive (CSRD)(COM(2021) 189) increases disclosure requirements for corporations along Taxonomy lines. This legislation, which came into effect in 2023, will be progressively rolled out starting from larger and listed companies and expanding to a majority of companies this decade. Provisions have been made for charities and non-profits to be exempt. However, one of the key consequences of disclosure requirements over funds through the SFDR is its waterfall effect; that is the imposition of indirect reporting requirements as investors pass-on their reporting responsibilities to their borrowers. Fourth, the proposed EU Green Bonds Standards (EU-GBS) COM(2021) 391 aims to gear bond proceedings toward Taxonomy-aligned projects and increase transparency through detailed reporting and external reviewing by auditors certified by the European Security Markets Authorities (ESMA). The main objectives of these legislative changes is to create additionality, that is, steer new finance into green activities (see Figure 1).   While this new legislation is poised to increase accountability and transparency, it also aims to encourage a better management of environmental risks. According to a recent report on banking supervision by the European Central Bank (ECB), real estate is one of the major sources of risk exposure for the financial sector (ECB, 2022). This includes both physical risks, those resulting from flooding or drought and, more relevant in this case, transitional risks, that is those derived from changes in legislation such as the EPBD and transposing national legislation. The ECB points to the need for a better understanding of risk transmission channels from real estate portfolios into the financial sector through enhanced data collection and better assessments of energy efficiency, renovation costs and investing capacity. At its most extreme, non-compliance with EU regulations could result in premature devaluation and stranded assets (ECB, 2022). In short, the introduction of reporting and oversight mechanisms connects legislation on housing’s built fabric, namely the EPBD, to financial circuits. On the one hand, the EU has been strengthening its requirements vis-à-vis energy efficiency over the last decades. The Energy Efficiency Directive (EED) suggested the introduction of Minimum Energy Performance Standards (MEPS) by Member States (Economidou et al., 2020), a rationale followed by France and the Netherlands for certain segments of the housing stock. Currently, policy-makers are debating on whether the EPBD’s recast (COM/2021/802) should incorporate MEPS and make decarbonisation an obligation for SHOs across the EU. On the other hand, legislation on green finance aims to produce incentives and oversight over investments in energy efficient renovation and new build, mobilising the private sector to cater to green projects (Renovation Wave (COM(2020) 662)). 

The review of this case study is structured to address aspects of architectural design, construction approach, and sustainability integration. The analysis draws on a range of data sources, including project design and access statements, sustainability statements, design drawings, planning applications, associated communications and archival records obtained from the planners, public records and the London Borough of Lambeth planning portal.   1. Design statement The project site stretches to approximately 0.86 hectares, 84 residential units at a density of 215 dwellings per hectare are planned to be housed on the site. The surrounding areas are characterised by the prevalence of historic conservation areas. The site is located on the western side of the Cotton Garden Estate and is known for its public park and distinctive 22-storey Ebenezer, Hurley and Fairford towers. To the north is the Walcot Road Conservation Area with its three-storey terraced houses. To the east is Renfrew Roadside, which contains several listed buildings, including the Magistrates Court, the former Lambeth Fire Station and Workhouse (later converted to Lambeth Hospital) and what is now The Cinema Museum (Mae, 2017). Figure 1 illustrates the location of the project within the urban fabric of London. In response to the unique characteristics and features of the site, the design team developed a comprehensive strategy to integrate the development. Firstly, the scale and massing have been carefully balanced in order to harmonize with the surrounding area. This is achieved through   the use of graduated massing and a deliberate emphasis on the incorporation of open spaces and parks (Mae, 2017). Secondly, the existing transport and vehicular access has been maintained to avoid creating new routes.  Thirdly, a car-free zone has been established, with the number of parking spaces on the site limited to eight, exclusively for residential units. Additionally, a number of bicycle parking bays have been installed to provide secure and convenient storage for cyclists. Fourthly, the "The Walk" concept has been implemented, offering a pedestrian route designed with human needs in mind, in an aim to promote connectivity between the site, parks, buildings, and existing public areas. This includes creating gateways and landmarks to enhance the sense of procession along the footpaths. Moreover, a balanced integration of soft and hard landscape elements was pursued to foster a sense of cohesive connectivity while preserving the site's architectural heritage (Mae, 2017). Figure 2 provides a comparative visual representation of the former site against the proposed design.   Figure 2 provides a comparative visual representation of the former site against the proposed design for Knight’s Walk. From a typological perspective, a total of 84 units have been developed, ranging in size from 54 square metres for the smallest units to 90 square metres for the largest. Phase one comprises 16 flats, including 10 one-bedroom flats, three two-bedroom flats and three three-bedroom flats. In contrast, phase two offers a broader choice with 15 one-bedroom flats, 38 two-bedroom flats and 15 three-bedroom flats. With regard to architectural design, three key design considerations were identified as being of particular importance (HDA, 2022; Mae, 2017). The primary concern was the accessibility of the site for its residents, with particular attention paid to the needs of senior citizens and those with special requirements. This emphasis is particularly pronounced in Phase One, where the majority of units have been designed to meet both the Building Regulations Part M (which provides guidance on access to and use of buildings, including facilities for disabled occupants and easy movement through a building), and the prescribed national standards for accessible spaces (Mae, 2017). Secondly, the efficient use of space was prioritised, with the use of simple and clean architectural lines to optimise the functionality within each unit and the circulation areas. Thirdly, the well-being of residents was a significant consideration, with each unit featuring a terrace overlooking the surrounding green spaces and parks. The overall distribution of flats in both phases is shown in Figure 3.   2. Construction In terms of construction methods, the project adopts a fabric-first approach that focuses on improving the properties of the building fabric, with the objective of optimising thermal performance, airtightness and moisture management. This approach is intended to reduce the necessity for additional mechanical or technical solutions, thereby achieving enhanced energy efficiency and comfort (Eyre et al., 2023). In addition, project planners have incorporated supplementary measures to improve construction processes (Mae, 2017). These include using a reinforced concrete structure in locations prone to thermal bridging, while avoiding cores as the primary structural support system. Furthermore, a strategy to rationalise the building’s "form factor" ensures a coherent visual progression of the building mass whilst mitigating thermal impacts such as overheating on the overall building envelope. Secondly, a balanced glazing ratio has been implemented to reduce direct thermal impacts, with the additional benefit of providing resistance to thermal mass. The use of light-coloured materials also serves to reduce the heat island effect and thermal conductivity between the exterior and interior of the building. Finally, the use of a cantilevered method, particularly in building extensions, reduces thermal bridging while improving the overall aesthetics of the structures.   ​​​​​​​3. Sustainability and energy Several methods to promote sustainability have been integrated into the building’s envelope. The project follows the three-point model known as the "energy hierarchy", which is based on the principles of "Be Lean", "Be Clean", and "Be Green". “Be Lean” emphasizes the planning and construction of buildings that consume less energy. "Be Clean" focuses on efficiently providing and consuming energy, while "Be Green" aims to meet energy needs through renewable sources (Muralidharan, 2021). 3.1. Energy and carbon strategy In line with energy hierarchy models, the project's energy strategy focuses on the building envelope and incorporates high-performance standards recommended by Passivhaus to optimise building mass and thermal boundaries. In addition, provisions have been made to future-proof the buildings by providing provisional spaces for future connection to planned district and central heating systems. Efforts to reduce carbon emissions centre on establishing accurate baseline emissions using the Standard Assessment Procedure (SAP), implementing passive measures such as natural ventilation and high-efficiency appliances, and reducing reliance on fossil fuels for electricity generation through the use of photovoltaic cells as a secondary energy source. As a result, the buildings have achieved a 35 per cent reduction in carbon emissions compared to local regulations and similar developments (Mae, 2017; TGA, 2017). 3.2. Overheating strategy Managing the risk of overheating has become an essential consideration in the design and construction of housing in the UK (Sameni et al., 2015). The quality of the indoor environment in any dwelling, particularly in summer, is vulnerable to excessive solar heat gain which is accentuated by the lack of rapid ventilation measures. To mitigate these challenges, the project's overheating strategy minimises internal heat generation through energy-efficient design and reduces heat gain through careful orientation, shading, windows, and insulation. Passive ventilation measures, such as natural cross-ventilation and fixed external shading, are also utilised. In addition, primary heating pipework is carefully planned to minimise losses, particularly when installed within the dwellings (TGA, 2017). 3.3. Policy and standards The project has been developed in accordance with a complex network of interrelated policies and standards at the national, regional and local levels, in addition to mandatory national sustainability guidelines. Notably, Building Regulations Part L, which sets out specific requirements for insulation, heating systems, ventilation and fuel use, and aim to reduce carbon emissions by 31 per cent compared to those of previous regulations. Knight's Walk introduced a new layer of mandatory requirements, designated as "regional" guidelines. These guidelines are specific to the Greater London area and serve as a reference for all developments. In addition to fulfilling the national and regional regulations, the project had to comply with the requirements set forth by the local councils. Furthermore, the developer's requirements, known as Lambeth's Housing Design Standards function as a clarifying framework, outlining the pertinent policies at the national and regional levels. As a result, the project has comfortably achieved an energy rating of B (based on the Standards Assessment Procedure calculations), with the potential to progress to an A rating. The project has developed a multi-level sustainability strategy and architectural language that considers climate, environment, and local needs, focusing on energy and carbon reduction. These strategies include encouraging active travel, increasing biodiversity and implementing adaptations to mitigate the effects of climate change through a drainage strategy and incorporating SuDS and tree planting. In addition, each flat has been fitted with mechanical ventilation with heat recovery, providing a constant supply of fresh, filtered air even when the windows are closed. All apartments are also equipped with energy-saving electrification systems to minimise electricity consumption (HDA, 2022).   ​​​​​​​4. Reflections The section highlights both the successful aspects and the potential areas for improvement identified in the previous sections by addressing the following questions: What methodologies were deployed within Knight’s Walk that can be classified as exemplifying ‘good’ practise? The comprehensive assessments conducted by the designers, covering a wide range of intervention areas, facilitated the formulation of a responsible phasing strategy that mitigated the social, economic, and environmental risks associated with large-scale development projects. The early provision of alternative, well-built housing for tenants who were displaced has fostered robust collaboration between developers, designers, and local communities. The project was developed in accordance with widely recognised accessibility standards, including compliance with Building Regulations Part M. A comprehensive assessment framework was employed to measure the quality of outcomes in line with national, regional, and local policies. In order to facilitate the adoption of improved energy efficiency strategies, consultation was undertaken with specialists versed in Passivhaus design standards. As a result of this consultation, it was determined that no additional standards were required. These strategies included the implementation of passive measures, such as massing, orientation, and material selection, complemented by high-efficiency mechanical ventilation systems, photovoltaic cells, energy-efficient appliances and well-insulated façade designs. As a result, the project achieved a Class B environmental performance during the operational phase and a diminished average national CO₂ emission for residential buildings by 80 per cent. The project's carbon production averaged 0.7 tonnes of CO₂ per year, with primary energy consumption ranging from 42 to 58 kilowatt hours per square metre (kWh/m2) (DLUHC, 2021). What are the potential weaknesses inherent to Knight’s Walk? Notwithstanding the robust practices that were put in place, several risks were identified, particularly in relation to the design approach that was selected. Although the fabric-first approach is regarded as a fundamental tenet of sustainable construction, it has not been without its detractors. A significant concern is the long-term variability in the performance of fabric-first buildings, which is contingent upon factors such as maintenance practices, occupant behaviour and climate fluctuations. Inadequate construction quality or maintenance practices can result in the deterioration of energy efficiency gains over time, underscoring the need for continuous monitoring and maintenance (Eyre et al., 2023). This could consequently result in a considerable increase in operational costs, thereby jeopardising the objective of housing affordability over the long term. Furthermore, buildings with high insulation using the fabric-first approach may be susceptible to overheating during the warmer seasons in certain climates, particularly if passive cooling strategies are inadequately integrated into the design (Eyre et al., 2023). This can lead to additional energy consumption for cooling purposes and counteract efforts to achieve highly efficient energy.