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.

Life Cycle Costing (LCC) is a method used to estimate the overall cost of a building during its different life cycle stages, whether from cradle to grave or within a predetermined timeframe (Nucci et al., 2016; Wouterszoon Jansen et al., 2020). The Standardised Method of Life Cycle Costing (SMLCC) identifies LCC in line with the International Standard ISO 15686-5:2008 as "Methodology for the systematic economic evaluation of life cycle costs over a period of analysis, as defined in the agreed scope." (RICS, 2016). This evaluation can provide a useful breakdown of all costs associated with designing, constructing, operating, maintaining and disposing of this building (Dwaikat & Ali, 2018). Life cycle costs of an asset can be divided into two categories: (1) Initial costs, which are all the costs incurred before the occupation of the house, such as capital investment costs, purchase costs, and construction and installation costs (Goh & Sun, 2016; Kubba, 2010); (2) Future costs, which are those that occur after the occupancy phase of the dwelling. The future costs may involve operational costs, maintenance, occupancy and capital replacement (RICS, 2016). They may also include financing, resale, salvage, and end-of-life costs (Karatas & El-Rayes, 2014; Kubba, 2010; Rad et al., 2021). The costs to be included in a LCC analysis vary depending on its objective, scope and time period. Both the LCC objective and scope also determine whether the assessment will be conducted for the whole building, or for a certain building component or equipment (Liu & Qian, 2019; RICS, 2016). When LCC combines initial and future costs, it needs to consider the time value of money (Islam et al., 2015; Korpi & Ala-Risku, 2008). To do so, future costs need to be discounted to present value using what is known as "Discount Rate" (Islam et al., 2015; Korpi & Ala-Risku, 2008). LCC responds to the needs of the Architectural Engineering Construction (AEC) industry to recognise that value on the long term, as opposed to initial price, should be the focus of project financial assessments (Higham et al., 2015). LCC can be seen as a suitable management method to assess costs and available resources for housing projects, regardless of whether they are new or already exist. LCC looks beyond initial capital investment as it takes future operating and maintenance costs into account (Goh & Sun, 2016). Operating an asset over a 30-year lifespan could cost up to four times as much as the initial design and construction costs (Zanni et al., 2019). The costs associated with energy consumption often represent a large proportion of a building’s life cycle costs. For instance, the cumulative value of utility bills is almost half of the cost of a total building life cycle over a 50-year period in some countries (Ahmad & Thaheem, 2018; Inchauste et al., 2018). Prioritising initial cost reduction when selecting a design alternative, regardless of future costs, may not lead to an economically efficient building in the long run (Rad et al., 2021). LCC is a valuable appraising technique for an existing building to predict and assess "whether a project meets the client's performance requirements" (ISO, 2008). Similarly, during the design stages, LCC analysis can be applied to predict the long-term cost performance of a new building or a refurbishing project (Islam et al., 2015; RICS, 2016). Conducting LCC supports the decision-making in the design development stages has a number of benefits (Kubba, 2010). Decisions on building programme requirements, specifications, and systems can affect up to 80% of its environmental performance and operating costs (Bogenstätter, 2000; Goh & Sun, 2016). The absence of comprehensive information about the building's operational performance may result in uninformed decision-making that impacts its life cycle costs and future performance (Alsaadani & Bleil De Souza, 2018; Zanni et al., 2019). LCC can improve the selection of materials in order to reduce negative environmental impact and positively contribute to resourcing efficiency (Rad et al., 2021; Wouterszoon Jansen et al., 2020), in particular when combined with Life Cycle Assessment (LCA). LCA is concerned with the environmental aspects and impacts and the use of resources throughout a product's life cycle (ISO, 2006). Together, LCC and LCA contribute to adopt more comprehensive decisions to promote the sustainability of buildings (Kim, 2014). Therefore, both are part of the requirements of some green building certificates, such as LEED (Hajare & Elwakil, 2020).     LCC can be used to compare design, material, and/or equipment alternatives to find economically compelling solutions that respond to building performance goals, such as maximising human comfort and enhancing energy efficiency (Karatas & El-Rayes, 2014; Rad et al., 2021). Such solutions may have high initial costs but would decrease recurring future cost obligations by selecting the alternative that maximises net savings (Atmaca, 2016; Kubba, 2010; Zanni et al., 2019). LCC is particularly relevant for decisions on energy efficiency measures investments for both new buildings and building retrofitting. Such investments have been argued to be a dominant factor in lowering a building's life cycle cost (Fantozzi et al., 2019; Kazem et al., 2021). The financial effectiveness of such measures on decreasing energy-related operating costs, can be investigated using LCC analysis to compare air-condition systems, glazing options, etc. (Aktacir et al., 2006; Rad et al., 2021). Thus, LCC can be seen as a risk mitigation strategy for owners and occupants to overcome challenges associated with increasing energy prices (Kubba, 2010). The price of investing in energy-efficient measures increase over time. Therefore, LCC has the potential to significantly contribute to tackling housing affordability issues by not only making design decisions based on the building's initial costs but also its impact on future costs – for example energy bills - that will be paid by occupants (Cambier et al., 2021). The input data for a LCC analysis are useful for stakeholders involved in procurement and tendering processes as well as the long-term management of built assets (Korpi & Ala-Risku, 2008). Depending on the LCC scope, these data are extracted from information on installation, operating and maintenance costs and schedules as well as the life cycle performance and the quantity of materials, components and systems, (Goh & Sun, 2016) These information is then translated into cost data along with each element life expectancy in a typical life cycle cost plan (ISO, 2008). Such a process assists the procurement decisions whether for buildings, materials, or systems and/or hiring contractors and labour, in addition to supporting future decisions when needed (RICS, 2016). All this information can be organised using Building Information Modelling (BIM) technology (Kim, 2014; RICS, 2016). BIM is used to organise and structure building information in a digital model. In some countries, it has become mandatory that any procured project by a public sector be delivered in a BIM model to make informed decisions about that project (Government, 2012). Thus, conducting LCC aligns with the adoption purposes of BIM to facilitate the communication and  transfer of building information and data among various stakeholders (Juan & Hsing, 2017; Marzouk et al., 2018). However, conducting LCC is still challenging and not widely adopted in practice. The reliability and various formats of building related-data are some of the main barriers hindering the adoption of LCCs (Goh & Sun, 2016; Islam et al., 2015; Kehily & Underwood, 2017; Zanni et al., 2019).

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.

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).

A precise and definitive definition of environmentally sustainable social housing remains elusive. Instead, it encompasses a bundle of interrelated terms such as low-impact buildings, sustainable buildings and environmentally responsible buildings, all of which are interwoven with the characteristics of social housing and its policy and development. This review examines the theoretical underpinnings of social housing and environmental sustainability at the EU level, outlines the challenges of integrating sustainability into housing and proposes an overarching definition of environmentally sustainable social housing. Social housing narratives Elsinga (2012) explains that social housing in the European Union is broadly described as a set of initiatives to provide high-quality and affordable housing for disadvantaged and middle-income groups, usually managed by public authorities (Elsinga, 2012). In the UK and the Netherlands, however, the management of social housing has largely been entrusted to non-profit organisations. This approach contrasts with that of Germany and Spain, where public subsidies are provided to commercial landlords in exchange for a fixed social rent and thus constitute a form of social housing. Granath Hansson and Lundgren (2019) further note that the historical development of social housing in the EU has involved a significant transfer of responsibility from local authorities to non-municipal providers, albeit under highly regulated practices such as the UK's managerialist approach (Granath Hansson & Lundgren, 2019). Priemus (2013) offers a definition that emphasises the regulatory framework and the role of the public sector in regulating social housing (Priemus, 2013). This definition identifies the target group as households unable to compete in the private housing market due to financial, physical or mental health problems or belonging to an ethnic minority or immigrant group. Bengtsson (2017), adopting a target group perspective, characterises social housing as a "system" designed to provide housing to resource-constrained households, with the requirement for their needs to be confirmed (Bengtsson, 2017). Although there is no universally accepted definition of social housing, it can be assumed that social housing functions as a system that supports households with limited financial resources by providing long-term accommodation. This system requires a mechanism to assess the needs of the target groups, ensuring that the housing is provided as a subsidy and not as a self-sustaining unit. Consequently, rents or prices within this system must be affordable and below market prices. Environmental sustainability narratives While there is no definitive definition of environmental sustainability specific to the EU in the literature, several scholars have contributed to understanding this concept from a global perspective and thus influenced its interpretation at the EU level. Notable contributions include those by Hey (2005), Portney (2015), Purvis et al. (2019) and Morelli (2011). Purvis et al. (2019) emphasise that environmental sustainability results from describing environmental protection goals and their interrelationships with broader concepts of the built environment. Environmental sustainability has evolved into a dynamic and multidisciplinary concept that is closely linked to concepts such as resilience, durability and renewability. Morelli (2011) states that environmental sustainability can be applied at different levels and encompasses tangible and intangible aspects (Morelli, 2011). Portney (2015) argues that environmental sustainability goals include conserving natural resources, improving people’s well-being, and promoting industrial efficiency without compromising societal development. The contemporary approach to implementing sustainability focuses on reducing the resource consumption of buildings (such as water and energy) and minimising waste production while improving the quality of the built environment. This approach goes beyond individual buildings and extends to the urban fabric of cities (Berardi, 2012; McLennan, 2004). The EU's approach to environmental sustainability is reflected in its directives, policies, initiatives and guidelines. An example of these initiatives is the European Green Deal (EC, 2019), which aims for a carbon-neutrality across Europe by 2050 while promoting sustainable economic growth (Fetting, 2020; Siddi, 2020). In addition, the EU emphasises the importance of integrating environmental concerns into various policy areas, including energy, transport, agriculture and industry. The EU Circular Economy Action Plan, for example, promotes an economy that minimises waste and supports sustainable consumption and production patterns (EC, 2020). Overall, the EU's approach to environmental sustainability emphasises the need for a comprehensive, integrated, and long-term perspective (Hermoso et al., 2022; Johansson, 2021). This approach considers the economic, social, and environmental dimensions of sustainability and emphasises the importance of international cooperation in addressing global environmental challenges (Fetting, 2020; Hermoso et al., 2022; Siddi, 2020). Integration imperatives and its challenges The realisation of environmentally sustainable social housing presents numerous challenges. The initial investment in sustainable building technologies and materials is often considerable, especially given the limited funds available for social housing projects. Compliance with ever-evolving environmental regulations further complicates the delivery of sustainable social housing. Consequently, there is an urgent need to adapt sustainable practices to different scales of social housing projects, which requires careful planning and adaptation to the specific needs and context of different developments (Oyebanji, 2014). Despite these challenges, the field of sustainable social housing offers significant opportunities for innovation and improvement. Technological progress continuously offers more efficient, cost-effective and sustainable solutions (IEA, 2022). In addition, robust policy frameworks and incentives are crucial for the adoption of sustainable practices (Fetting, 2020). Another crucial element is the active participation of different stakeholders in the design and maintenance of housing, which can significantly improve both sustainability and social cohesion (Shirazi & Keivani, 2019). The way forward Environmentally Sustainable social housing is becoming increasingly important as it represents both a possible future and an ambitious goal. It envisions an environmentally responsible housing sector without compromising its development capacity (Morgan & Talbot, 2001; Oyebanji, 2014; Winston, 2021). It aims to create housing that minimises its environmental footprint, promotes the well-being of its residents and provides affordable housing opportunities. It also aims to meet the housing needs of vulnerable and low-income groups while promoting sustainable development and addressing climate and environmental issues (Udomiaye et al., 2018).

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.).