1 Introduction

Urbanization has dramatically reshaped the social and economic landscapes of modern cities, with significant implications for housing accessibility and quality. Housing, a fundamental human need, remains a huge challenge in Africa, particularly among low-income families [1,2,3]. The United Nations has described the right to adequate housing as an inalienable and fundamental human right [4]. The issue of housing crisis is exacerbated by the rapid urbanization occurring across the continent. The African Development Bank Group (AFDB) indicates that urbanization is one of the key transformations Africa will experience in the twenty-first century, driven largely by rural–urban migration [5]. In 2021, the urbanization rate in Africa reached 44% and is projected to hit 60% by 2050 [6]. This transformation highlights the urgent need for sustainable housing strategies that can keep pace with urban growth, foster resilience in African cities, and uplift low-income families.

The urgency of addressing housing issues is demonstrated by the proliferation of informal settlements and slums, which are characteristic of many rapidly urbanizing African cities [7,8,9]. These areas often lack access to basic services such as water, sanitation, and healthcare, exacerbating poverty and inequality [10, 11]. Moreover, misconceptions and negative stereotypes about affordable housing often hinder the development and acceptance of necessary housing initiatives. Cities that fail to provide affordable housing solutions not only drive out residents but also lose potential workers and stymie local economic growth.

Sustainable innovative affordable housing (SIAH) is a relatively new and evolving field that has received growing interest from scholars, practitioners, and policy makers over the last few years, due to the social, environment and economic benefits [4]. The emergence of innovative construction methods, materials and technologies in the construction industry has been projected to enhance the effective delivery of sustainable affordable housing [12, 13]. However, current literature reveals a significant gap in understanding the full spectrum of strategies that can effectively address the housing needs of low-income families in Africa. While existing research has documented various aspects of housing policy and practice, comprehensive analyses on sustainable and inclusive housing solutions are lacking. For instance, Gbadegesina and Marais [14] profile housing policy research in Africa, focusing on its scale and quality. Similarly, Moghayedi et al. [4] identify critical success factors for sustainable, innovative, and affordable housing, emphasizing energy efficiency, tenure security, and affordability. Additionally, Manomano et al. [15] highlight issues such as corruption, mismanagement, and inadequate materials in South African housing. Despite these insights, there is still a need for an integrated approach on the full spectrum of housing strategies that considers spatial justice and sustainability in developing effective housing strategies for low-income families.

Spatial justice emphasizes the fair and equitable distribution of resources and opportunities across different geographical areas, highlighting the right to a healthy and safe living environment for all [16]. Inclusive housing is an essential component of spatial justice, as it provides secure and affordable shelter for all residents, regardless of their socioeconomic status. Sustainability, in this context, emphasizes the need for housing solutions that not only meet the present needs of low-income families but also ensure the preservation of resources and environmental quality for future generations. Achieving spatial justice through sustainable housing involves not only providing affordable shelter but also integrating principles of environmental stewardship, community resilience, and social equity into urban development strategies. This approach not only addresses immediate housing challenges but also contributes to long-term urban sustainability by fostering liveable and inclusive communities.

This paper aims to bridge the gap in literature on low-income housing in Africa by exploring a range of strategies for sustainable housing solutions specifically tailored for low-income families in Africa. It addresses the broader issue of affordable housing through a focused examination of innovative and inclusive approaches that promote sustainability and spatial justice. The study is guided by the following research questions:

  1. 1.

    What are the key sustainable housing strategies that can be applied to low-income housing in African cities?

  2. 2.

    What are the potential benefits and drawbacks of each strategy within the African context?

The paper provides a comprehensive understanding of how sustainable housing initiatives can be implemented effectively to enhance spatial justice and improve living conditions for low-income families in African cities. The paper makes a significant contribution to the existing body of knowledge by providing a detailed analysis of sustainable housing strategies through the lens of sustainability and spatial justice. It fills a critical research gap by linking theoretical concepts with practical applications, offering new insights into the intersection of urbanization, housing, and social equity in Africa.

The findings of the paper reveal that various innovative approaches can reshape the landscape of sustainable housing solutions in Africa. Upcycling leverages existing materials to reduce construction costs and environmental impact while enhancing durability and energy efficiency. However, challenges such as material scarcity and quality control, alongside societal resistance, hinder widespread adoption. Micro-housing optimizes space and energy use, fostering affordability and community cohesion. Yet, limitations in accommodating larger families and regulatory complexities pose significant challenges. Community-led housing empowers residents, promoting social inclusion and sustainable practices. However, securing urban land and financial resources remains a daunting task, demanding substantial time and effort. Co-housing models foster economic efficiency and resilience through shared resources, yet face hurdles in securing suitable urban plots and gaining social acceptance. Green building practices improve environmental sustainability and indoor air quality but face initial cost barriers, particularly for low-income groups without financial support. 3D printing holds promise for cost-effective and rapid construction with minimal waste, though scaling up remains constrained by technology readiness, regulatory frameworks, and material limitations. These findings have important practical implications, as they can inform policy and practice in the pursuit of sustainable and equitable urban development. Highlighting successful case studies and providing actionable recommendations, the paper serves as a valuable resource for policymakers, urban planners, and housing advocates working to address the housing crisis in Africa.

The paper is organized as follows: The next section presents literature review on low-income families, inclusive housing, sustainable housing, and conceptualizes spatial justice and its application in the context of housing. The subsequent section presents the methodology of the study. Following this, the paper examines different strategies for providing inclusive housing for low-income families in Africa, drawing on case studies and examples from across the globe. It explores the potential of mixed-use developments, incremental housing, low rental housing, inclusionary housing, three-dimensional (3D) printing, upcycling, micro-housing, community-led housing, co-housing, and green building practices in promoting sustainable solutions for housing in African cities. Finally, the paper concludes by summarizing the key findings and discussing the implications for policy and practice, emphasizing the need for a holistic and integrated approach to housing that considers the social, economic, and environmental dimensions of urban development. The paper also highlights the importance of community participation and engagement in housing planning and design, as well as the need for innovative financing models to ensure the sustainability of housing initiatives.

2 Literature review

2.1 Low-income families and inclusive housing

Low-income families in Africa face unique challenges in accessing adequate housing. These families often reside in informal settlements with limited access to basic services and infrastructure [17, 18]. Understanding the specific needs of low-income families is essential for designing housing solutions that are both affordable and sustainable. Policies aimed at supporting incremental housing and community-led initiatives can empower low-income families to improve their living conditions over time [19]. Inclusive housing refers to the provision of secure and affordable shelter for all residents, regardless of their socioeconomic status. It ensures that housing solutions are accessible to marginalized groups and promotes social equity. In the African context, inclusive housing is crucial for addressing the needs of low-income families who are often excluded from formal housing markets [8, 17]. Strategies such as mixed-use developments and inclusionary housing policies are instrumental in creating inclusive housing environments [20].

2.2 Defining sustainable housing

Sustainable housing is an emerging knowledge domain [4, 12]. Scholars contend that the sustainability aspect of affordable housing has been largely overlooked due to insufficient motivation and incentives for developers, alongside restrictive regulatory and policy challenges [21]. This often leads to the construction of substandard, unsustainable housing, which proves costly to maintain in the long run [4, 14]. Nevertheless, efforts to mainstream sustainability principles into affordable housing projects through the adoption of modern methods of construction, like innovative prefabricated construction methods (IPCMs), have been observed [22].

Moghayedi et al. [4] defined Sustainable Innovative Affordable Housing (SIAH) as the incorporation of innovative methods, practices, materials, and technologies in the development of sustainable and affordable housing. Sustainable housing, as used in this paper, aligns with the holistic definition provided by the United Nations and the Brundtland Commission. The Brundtland Commission's definition of sustainability emphasizes meeting the needs of the present without compromising the ability of future generations to meet their own needs. Sustainable housing, therefore, encompasses three main dimensions: environmental, social, and economic sustainability [23]. This paper adopts this comprehensive approach, considering how different housing strategies contribute to sustainability across these dimensions. Environmental sustainability in housing focuses on minimizing the ecological footprint through the use of eco-friendly materials, energy-efficient technologies, and sustainable construction practices. For instance, 3D printing of houses uses materials like recycled plastics and minimizes waste through precise construction processes [24, 25]. Upcycling, another innovative approach, involves repurposing waste materials to create building components, thereby reducing landfill waste and resource consumption [26]. Green building practices also fall under this category, emphasizing the use of renewable energy sources, natural ventilation, and sustainable building materials [27, 28].

Social sustainability in housing addresses the need for inclusive, equitable, and community-oriented living environments. This dimension ensures that housing solutions promote social cohesion, community participation, and access to essential services. Co-housing and community-led housing models are prime examples of socially sustainable housing strategies. These models foster a sense of community, reduce social isolation, and encourage collaboration among residents [29, 30]. Inclusionary housing policies, which mandate a percentage of affordable housing in new developments, also enhance social sustainability by promoting diverse and inclusive communities [31]. Economic sustainability in housing involves providing affordable housing solutions that are financially viable over the long term. This includes reducing construction and maintenance costs, ensuring energy efficiency to lower utility bills, and supporting economic opportunities for residents. Incremental housing, where homes are built in stages as financial resources become available, exemplifies economic sustainability by allowing low-income families to improve their housing conditions progressively [19]. Similarly, 3D printing can drastically cut construction costs and time, making housing more affordable for low-income families [65].

2.3 Integrating sustainable housing strategies

A truly sustainable housing strategy for low-income families in Africa requires an integrated approach that addresses all three dimensions of sustainability. Mixed-use developments, for example, combine residential, commercial, and recreational spaces, promoting economic activity while reducing the need for transportation [32]. Incorporating green building practices into these developments can further enhance their environmental sustainability by reducing energy consumption and carbon emissions [33]. Co-housing and incremental housing models can be integrated to provide both social and economic benefits. By sharing resources like kitchens and laundry facilities, co-housing communities can reduce living costs and foster social interactions. At the same time, allowing residents to incrementally build and upgrade their homes can make these communities financially accessible to low-income families [34].

Studies from other developing regions offer valuable lessons for sustainable housing in Africa. Ross et al. [20] highlight the importance of community involvement and locally sourced materials in creating sustainable housing solutions. Their research demonstrates the need for adaptable housing models that can respond to the specific social, economic, and environmental contexts of different regions. In South Africa, sustainable housing initiatives have focused on integrating green building practices with social housing projects to create environmentally friendly and socially inclusive communities [20]. These projects demonstrate the potential of combining various sustainable housing strategies to address the complex challenges faced by low-income families.

2.4 Spatial justice in the context of low-income housing

Spatial justice is the concept that all people, regardless of their socioeconomic status, race, ethnicity, or other identity factors, should have equal access to resources, opportunities, and services within their physical and social environments [16]. This includes access to affordable and safe housing, transportation, healthcare, education, employment, and other essential services. Spatial justice recognises that inequalities in access to resources and opportunities are often closely tied to cities' and communities' physical and social structures. For example, urban planning decisions, such as the location of affordable housing, public transportation, and green spaces, can significantly impact residents' quality of life and well-being. The concept of spatial justice emphasises the need for policies and initiatives that promote equitable access to resources and opportunities for all residents, regardless of where they live or their socioeconomic status [35]. This includes strategies such as affordable housing initiatives, public transportation improvements, and community development programs that prioritise the needs of marginalised and disadvantaged communities [17, 36]. Ultimately, spatial justice seeks to create cities and communities that are equitable, inclusive, and sustainable, where all residents have the opportunity to thrive and reach their full potential [18, 36].

In the context of low-income families, spatial justice refers to the need for policies and initiatives that address the specific challenges low-income residents face in accessing affordable housing, basic services, and opportunities for economic mobility [35]. Urban areas often concentrate on poverty, with many low-income residents living in informal settlements or slums with inadequate housing and limited access to services. Spatial justice for low-income families requires addressing the root causes of poverty and inequality, including discriminatory housing and urban planning practices, lack of access to basic services and infrastructure, and limited economic opportunities [16]. This includes policies and initiatives that promote affordable housing options, such as social housing programs, community land trusts, and rent control measures [37]. In addition, policies and initiatives that improve access to basic services and infrastructure are crucial for promoting spatial justice for low-income families. These initiatives can help low-income residents to access economic opportunities and build assets that can help them escape poverty and build a better future for themselves and their families.

3 Methodology

A rapid review methodology was adopted to quickly gather and synthesize existing literature on sustainable housing strategies relevant to low-income families in African cities. This approach allowed for an efficient yet comprehensive examination of the topic on sustainable housing strategies for low-income families, ensuring the findings are timely and applicable. The literature search was conducted using academic databases such as Google Scholar, JSTOR, Scopus, and Web of Science. The search utilized keywords including "sustainable housing," "affordable housing," "low-income families," "Africa," "urbanization," "spatial justice," "inclusive housing," "green building," "incremental housing," "3D printing housing," and "community-led housing." The search focused on English-language articles published between 2000 and 2024 to include recent advancements and trends.

To ensure relevance and quality, the inclusion criteria based on focus on sustainable housing strategies, discussion of housing for low-income families, coverage of urbanization and spatial justice, and peer-reviewed journal articles, conference papers, and policy documents, was applied. Primary data sources included academic journals, conference proceedings, and policy documents from international organizations (e.g., UN-HABITAT, African Development Bank), as well as case studies from African countries and best practices from other parts of the word. Grey literature such as government reports and NGO publications were also reviewed for a broader perspective. The collected literature was analyzed using thematic analysis, involving initial reading and re-reading of the literature to understand the content, Coding—highlighting significant phrases, sentences, or sections related to sustainable housing strategies, challenges, and benefits, and Theme Development—grouping codes into broader themes. To ensure the validity and reliability of the findings, we applied cross-referencing of findings from multiple sources and data types to corroborate results. Although based on a literature review and not primary data collection, ethical considerations included proper citation and acknowledgment of sources, respecting intellectual property rights, and maintaining objectivity and transparency in the analysis and reporting of findings.

The results of the rapid review are presented in the subsequent sections, focusing on the identified sustainable housing strategies and their implications for low-income families in Africa. Each strategy is analyzed in terms of its potential benefits, challenges, and suitability for addressing the housing needs in rapidly urbanizing African cities.

4 Results: strategies for sustainable innovative affordable housing (SIAH) for low-income families in Africa

This section presents the various innovative strategies for solving housing problems for low-income families in Africa. These are Mixed-use developments, Incremental housing, Low rental housing, Inclusionary housing, Three-dimensional (3D) printing, Upcycling, Micro-housing, Community-led housing, Co-housing, and green building practices (Fig. 1). While the presentation comprises a blend of strategies, methods, tools, and practices, it is essential to note that these categories are not strictly delineated in this paper. For example, while 3D printing can be categorized as a tool/method, while green building is classified as a practice. This paper, however, presents all of these under "strategies/approaches" as it is not the aim of the paper to delve deeply into clear classifications. Furthermore, it is important to recognize that some strategies may exhibit similarities, albeit under different names across various contexts or countries. This means that these approaches/strategies are not mutually exclusive and can often overlap or be integrated. The paper also discusses how these approaches could be utilized together to address housing challenges comprehensively. Perhaps future research could delineate the strategies into distinct categories based on their nature and purpose (strategy, method/tool, practice etc.), providing a clearer framework for understanding and implementation.

Fig. 1
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Source: Authors

Sustainable and Innovative strategies for solving housing problems in African cities.

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4.1 Mixed-use developments

Mixed-use development is an urban design strategy that integrates different land uses, such as residential, commercial, and institutional, within the same development [38]. Mixed-use development aims to create a more sustainable and livable urban environment by reducing the need for long commutes and promoting walkable neighbourhoods [39, 40]. This strategy has been increasingly used in urban areas to promote sustainable housing solutions for low-income families. Mixed-use development can provide several benefits for low-income families, such as improved access to amenities by integrating commercial and institutional uses within residential areas; mixed-use developments can provide residents with better access to essential amenities, such as healthcare, education, and retail services [41]. Mixed-use developments also reduce the need for long commutes by providing residents with access to employment opportunities within the same development or nearby [40, 41]. This can significantly reduce transportation costs, which can significantly burden low-income families. Creating a more walkable and livable environment, mixed-use developments also promote social interaction among residents and create a sense of community [42]. Figure 2 shows mixed-use development in Boulder, Colorado.

Fig. 2
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Mixed-use development in Boulder, Colorado. Source: [43]

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There are several successful examples of mixed-use development being used as a strategy for sustainable housing solutions for low-income families. For example, the Kibera Hamlets in Nairobi, Kenya, is a mixed-use development that integrates residential, commercial, and institutional uses within the same development [44]. The development provides residents with access to essential amenities, such as healthcare, education, and retail services, and has helped to improve the quality of life for residents. Another good example of mixed-use housing is Kigali Heights in Rwanda. Kigali Heights is a mixed-use development project that includes low-income housing units as well as commercial space. The project, financed by the African Development Bank, consists of one and two-bedroom apartments designed to provide affordable housing for low-income earners.

However, implementing mixed-use development as a strategy for sustainable housing solutions for low-income families has its own problems. For example, mixed-use development requires large tracts of land, which may not be available in densely populated urban areas [45]. Mixed-use developments also require significant infrastructure investments, such as roads, water supply, and sewage systems, which may not be feasible in some areas. Further, mixed-use developments require significant upfront investments, which may be challenging to secure in areas with limited financing options [41]. While there are several challenges associated with implementing mixed-use development, mixed-use development is a promising strategy for promoting sustainable housing solutions for low-income families in Africa. Successful case studies demonstrate how the benefits of this strategy can outweigh the challenges [44].

4.2 Incremental housing

Incremental housing is an approach to housing development that involves building homes in stages over time rather than all at once [46]. This approach allows residents to start with a basic structure and gradually add on as their needs and resources allow. The strategy has been increasingly used to promote sustainable housing solutions for low-income families. This is because incremental housing is often more affordable than traditional housing development, as residents can build and improve their homes over time as their resources allow [46]. Incremental housing also allows residents to adapt their homes to their changing needs and circumstances over time [47]. Figure 3 shows incremental housing in Villa Verde.

Fig. 3
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Incremental Housing in Villa Verde. Source: [48]

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Various case studies also demonstrate that incremental housing empowers residents to take control of their own housing development and improve their living conditions [19, 49]. For example, Thailand's Baan Mankong program has helped provide affordable housing for over 90,000 low-income families through incremental housing development [50]. The program also empowered residents to take control of their own housing development and improve their living conditions.

There are also cases of attempts in adopting incremental housing strategies in various African cities, with varying degrees of success. In Kibera, one of Africa's largest informal settlements, many residents use incremental housing strategies. Families initially construct basic shelters using affordable and locally available materials [51]. Over time, as they save money or gain access to microfinance, they gradually improve their homes by adding more durable materials, additional rooms, or sanitation facilities [51]. Freedom Park in Cape Town, is another example of an organized incremental housing project supported by the South African government [52]. Initially, the government provides serviced plots with basic infrastructure such as water, sanitation, and electricity. Residents then build their homes incrementally, often starting with temporary shelters and gradually improving them. This approach helps residents to own their land and develop their homes at a manageable pace. In Ethiopia, the Integrated Housing Development Program (IHDP) promotes incremental housing by providing affordable land and technical assistance to low-income families [53]. The program encourages families to start with a basic structure and gradually improve their homes.

However, incremental housing development requires access to basic infrastructure, such as water and sanitation, which may not be available in some areas [19]. Incremental housing development may also require secure land tenure, which may not be available in areas with insecure land tenure systems. Further, this housing development approach also requires access to financing, which may be difficult to secure in areas with limited financing options [19].

4.3 Low-rental Housing

Another innovative strategy for solving housing problems for low-income families in Africa is low-rental housing. Low-rental housing is a housing development approach that provides affordable rental housing units to low-income families in urban areas [54, 55]. This strategy has been increasingly used to promote sustainable housing solutions for low-income families as it provides affordable housing options for families who may not be able to afford market-rate housing [56]. Studies also show that low-rental housing provides stable housing options for low-income families at risk of homelessness or housing insecurity [54, 56]. Figure 4 shows a low-rental housing project in Newcastle, South Africa.

Fig. 4
figure 4

Low-rental Housing project in Newcastle, South Africa. Source: [57]

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A good example of low-rental housing is Buhole Gardens, in Dar es Salaam, Tanzania. The project is designed to provide affordable housing for low-income earners and has 816 units consisting of one-, two-, and three-bedroom apartments. The project was financed by the government of Tanzania and the African Development Bank. East Gate Residences in Ghana is another low-income housing project in Accra, Ghana. The project has 628 units of one-, two-, and three-bedroom apartments. The World Bank and the government of Ghana financed the project. LagosHOMS is another low-income housing project located in Lagos, Nigeria [58]. The project has over 1,000 units of one-, two-, and three-bedroom apartments. The Lagos State government financed the project and is designed to provide affordable housing for low-income earners [59]. Jabulani Heights in South Africa is another low-cost housing project in Soweto, South Africa. The project has 1,176 units, financed by the government of South Africa and designed to provide affordable housing for low-income earners. The case studies demonstrate the potential of this strategy in reducing homelessness and housing insecurity. However, low-rental housing may require significant upfront investments, which may be difficult to secure in areas with limited financing options. Low-rental housing also requires access to affordable land, which may not be available in densely populated urban areas. Further, ongoing maintenance and management are required, which may be challenging in areas with limited resources and infrastructure.

4.4 Inclusionary housing

Inclusionary housing, also known as affordable housing or inclusionary zoning, is a strategy that requires a percentage of new residential developments to be set aside for affordable housing units [60, 61]. This percentage can vary depending on the location, market demand, and other factors. The affordable units are then sold or rented to households that meet certain income criteria, typically those who earn less than the area median income. Inclusionary housing policies provide affordable housing options to low and moderate-income households that would otherwise be priced out of the market [61]. Inclusionary housing policies can also help prevent the displacement of existing residents due to gentrification and development pressures by ensuring that affordable housing options are available in new developments [60]. Figure 5 shows an example of inclusionary social housing in South Africa.

Fig. 5
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Inclusionary social housing in South Africa. Source: [62]

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Economic diversity is also enhanced by inclusionary housing policies as they maintain and enhance economic diversity in urban areas, allowing low and moderate-income households to live in areas with better job opportunities and amenities. Studies also point to other benefits of inclusionary housing, like improved health and well-being and environmental benefits [31, 63]. For example, inclusionary housing policies can improve the health and well-being of low-income households by providing stable, safe, and affordable housing options. Further, inclusionary housing policies can promote sustainable urban development by encouraging compact and efficient land use, reducing commuting distances, and reducing greenhouse gas emissions. However, implementing inclusionary housing policies can be challenging, particularly in areas with high land costs and low demand for affordable housing. Further, inclusionary housing policies may face legal challenges, particularly in areas with strong property rights and anti-regulatory sentiments [63]. Inclusionary housing policies can also reduce the profitability of new residential developments, which may discourage developers from building new housing [31]. Finally, inclusionary housing policies can also face political opposition from developers, property owners, and other stakeholders who may see it as a threat to their interests [31, 63]. Thus, policymakers should carefully consider the local context and design policies that are effective, feasible, and equitable to ensure that they meet the needs of all stakeholders.

4.5 Three-dimensional (3D) printing

Three-dimensional (3D) printing has recently been hailed as a potential solution for quickly and efficiently building housing, and this promise is now becoming a reality [13]. 3D printing of houses is an innovative approach to housing development that involves using 3D printers to construct homes layer by layer [24, 25]. This approach can be used to construct homes using a variety of materials, including concrete, plastic, and even recycled materials. A study by Moghayedi et al. [13] “Revolutionizing affordable housing in Africa: A comprehensive technical and sustainability study of 3D-printing technology” affirm the potential of 3D-printing as a sustainable and efficient mechanism for revolutionizing the African housing sector by improving performance and expediting delivery. Figure 6 illustrates a 3D-printed house in Germany.

Fig. 6
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3D printed house in Germany. Source: [64]

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3D printing of houses has the potential to provide several benefits for low-income families, such as affordability by significantly reducing construction costs and making housing more affordable for low-income families [25]. Another notable advantage of 3D printing is the speed of construction. 3D printing of houses can significantly reduce construction time, allowing homes to be built more quickly and efficiently [25]. 3D printing is also strongly associated with sustainability by reducing waste, using recycled materials, and minimising the carbon footprint of construction [65]. There are several successful examples of 3D printing of houses being used as a strategy for sustainable housing solutions for low-income families. For example, in 2018, a 3D-printed housing project was launched in Mexico to provide affordable housing to families in need [66]. The project used a 3D printer to construct the walls of the homes, reducing construction costs by up to 50% and construction time by up to 80% [65]. Project Milestone in Eindhoven, the Netherlands, consists of five 300-square-foot homes made up of 24 large concrete structures of various shapes and sizes. The blocks are printed at a nearby factory in about five days and assembled on-site. ICON, a 3D-printing construction company in the USA, completed neighbourhood projects in Mexico and Texas using 3D printing technology for building homes [67, 68].

The government of Dubai has set a goal to have a quarter of new buildings in the country 3D printed by 2030 and has dedicated a district on the outskirts of the capital for 3D printing construction [69]. These are just a few examples of the many 3D-printed houses that have been built or are currently being built around the world, demonstrating how 3D printing technology has the potential to revolutionise the construction industry by offering faster construction times, lower costs, and increased design flexibility. However, there are some challenges associated with implementing 3D printing of houses as a strategy for sustainable housing solutions for low-income families. Firstly, 3D printing of houses is still a relatively new technology, and the capacity for large-scale production is limited. Secondly, there may be regulatory barriers to implementing 3D printing of houses, particularly in areas with strict building codes and regulations. Thirdly, while 3D printing of houses can use a variety of materials, the range of materials that can be used is still somewhat limited. Nevertheless, 3D printing of houses is a promising strategy for promoting sustainable housing solutions for low-income families. Through its potential to significantly reduce construction costs and time, 3D printing of houses can provide affordable and efficient housing options for low-income families in Africa.

4.6 Upcycling

Upcycling involves repurposing existing materials, such as shipping containers, industrial scraps, or discarded building materials, to create affordable and sustainable housing option [70]. Upcycling can be done on a small scale, such as using reclaimed wood to make furniture, or on a large scale, such as using shipping containers to construct multi-story buildings. It has emerged as another innovative and sustainable solution to address housing challenges for low-income families. Upcycling has several benefits as a sustainable housing solution for low-income families, such as reduced waste, thus reducing the environmental impact of waste disposal [71]. Upcycling materials that would otherwise be discarded can significantly reduce the cost of constructing homes, making them more affordable for low-income families. Upcycled materials, such as shipping containers and industrial scraps, are often more durable and weather-resistant than traditional building materials. Figure 7 shows container homes for low-cost housing in South Africa.

Fig. 7
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Container homes for low-cost housing in South Africa. Source: [72]

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Upcycling can also promote energy efficiency by using materials that have insulating properties, reducing the need for heating and cooling. Further, upcycling can create unique and visually appealing homes that can contribute to the character of the community. Despite its benefits, upcycling also faces several challenges as a sustainable housing solution for low-income families, such as the limited availability of materials. Upcycling requires access to materials suitable for construction, which may be limited in some areas. Upcycling may also be subject to regulatory challenges, such as building codes and zoning regulations, making obtaining permits and approvals in some African countries difficult. Quality control is also very critical. Upcycling requires skilled labour and quality control to ensure the materials are safe, durable, and meet building standards. Further, upcycling is still a relatively new concept in some African countries, which may limit its acceptance and adoption as a sustainable housing solution. Finally, some people may perceive upcycled homes as inferior in quality compared to traditional homes, limiting their appeal and value. Regardless of some challenges, upcycling can be an innovative and sustainable strategy for addressing the housing challenges for low-income families in Africa.

4.7 Micro-housing

Micro-housing is a strategy for sustainable housing solutions that prioritises efficiency and affordability in housing for low-income urban residents [73, 74]. Micro-homes are designed to maximise the use of limited space, often through the use of multifunctional furniture, foldable and expandable features, and vertical space [74]. Figure 8 shows an example of a micro-house.

Fig. 8
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Micro housing proves that affordable architecture can be beautiful. Source: [75]

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Micro houses can be built using various materials, such as wood, steel, or shipping containers, and can be located in urban areas close to amenities and public transportation. Micro-housing is more cost-effective compared to traditional housing, thus providing affordable options for low-income urban residents. Micro-homes are also typically built using sustainable and environmentally friendly materials, reducing the carbon footprint of housing construction [76]. Innovatively, micro-homes can be easily relocated, providing greater mobility and flexibility for low-income urban residents who may need to move frequently. Figure 9 shows an example of a micro house that can be relocated.

Fig. 9
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Micro-house that can be relocated. Source: [77]

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Micro-homes are designed to maximise energy efficiency, reducing energy consumption and costs for residents. Community cohesion can also be enhanced as micro-homes can be built in clusters or communities, promoting social interaction and community cohesion among residents [78]. Despite its benefits, micro-housing also faces several challenges as a sustainable housing solution for low-income families, such as limited space. Micro-homes are designed to maximise limited space, which can be challenging for some residents who may need more space for their families or belongings. Micro-housing may also be subject to regulatory barriers, such as zoning and building codes, making obtaining permits and approvals difficult [78]. Further, micro-homes may also be perceived as low quality or temporary, which can limit their acceptance and appeal among residents and the broader community.

4.8 Community-led housing

Community-led housing projects involve residents working together to design and build their own homes, focusing on sustainability and affordability [79]. Community-led housing is particularly relevant for urban areas with a shortage of affordable housing for low-income residents [80]. Low-income families often face a range of challenges when it comes to finding suitable housing, including high housing costs, inadequate living conditions, and limited access to basic services such as clean water and sanitation [1, 2]. This approach puts people at the centre of the housing development process and empowers them to create homes that meet their needs, aspirations, and values [79]. Figure 10 shows residents planning their community-led housing together.

Fig. 10
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Residents planning together their community-led housing. Source: [81]

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Community-led housing models include cooperative housing, community land trusts, and self-help housing [79, 80, 82]. In cooperative housing, residents collectively own and manage the housing development, sharing responsibilities for maintenance, repairs, and decision-making [82]. In community land trusts, a nonprofit organisation owns the land on which the housing is built, while residents own the homes and pay a lease for the land use [83]. Self-help housing involves residents taking an active role in the construction of their homes, often with support from government or nonprofit organisations [84]. One of the key benefits of community-led housing is that it can provide affordable housing for low-income residents. Involving residents in the development process can also foster a sense of community ownership and pride, leading to better maintenance and upkeep of the housing development over time [84]. Another benefit of community-led housing is that it can promote social and economic inclusion by providing opportunities for low-income residents to become homeowners and build equity [79, 80]. This can help to reduce the wealth gap between low-income and high-income households and promote economic mobility. Community-led housing can also promote environmental sustainability by incorporating green design principles, such as energy-efficient building materials, renewable energy sources, and water-saving technologies [85].

4.9 Co-housing

Co-housing involves multiple families living together in a shared space, each with their own private living quarters [34]. Co-housing communities often share resources such as kitchens, gardens, and laundry facilities, which can help reduce the overall environmental impact of the community [86]. Co-housing has recently gained popularity as a sustainable housing solution for low-income families. Co-housing communities are typically made up of a group of people who come together to design and build a shared living space that promotes social interaction, collaboration, and sustainability. In a co-housing community, residents typically have their own private living space but share common areas such as kitchens, gardens, and community spaces [29]. This type of living arrangement can promote social cohesion and reduce the sense of isolation that many low-income urban residents experience [30]. Figure 11 shows co-housing in Vancouver.

Fig. 11
figure 11

Co-housing in Vancouver. Source: [87]

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Co-housing communities can be designed with sustainability in mind, incorporating green building techniques and materials and renewable energy sources such as solar panels or wind turbines [88, 89]. In addition, many co-housing communities prioritise sustainable practices such as composting, gardening, and recycling, which can help reduce waste and promote environmental stewardship [85]. One of the key benefits of co-housing as a sustainable housing solution for low-income families is that it can be more affordable than traditional housing options [90]. Sharing resources such as kitchens and community spaces, residents can reduce their living costs and better use limited resources [34]. Another benefit of co-housing is that it can promote social and economic inclusion by providing opportunities for low-income residents to live in a community with a diverse mix of people. This can help to reduce social isolation and build stronger, more resilient communities. In addition, co-housing can be a particularly attractive option for low-income families with children, who may benefit from the shared childcare resources and communal spaces that are often available in co-housing communities [34, 90]. Co-housing can also provide a supportive environment for older adults, who may appreciate the social and practical benefits of living in a community with other people. However, there are some challenges associated with co-housing as a sustainable housing solution for low-income families. One of the main challenges is finding suitable land in urban areas where land is often scarce and expensive. In addition, building and maintaining a co-housing community requires a significant amount of time, energy, and resources, which can be difficult for low-income residents with limited access to capital or working multiple jobs to make ends meet [34].

4.10 Green building practices

Sustainable building practices, such as using environmentally friendly materials, incorporating energy-efficient technologies, and maximising natural light and ventilation, can help reduce the environmental impact of housing projects [27, 28]. Green building practices are a set of sustainable construction methods that can be used to reduce the environmental impact of housing development while also improving the health and well-being of occupants [91, 92]. Green building practices can be particularly beneficial for low-income families, who often face challenges related to inadequate living conditions, limited access to basic services such as clean water and sanitation, and exposure to environmental toxins. Figure 12 shows an example of a low-cost rental green building apartment. People living in low-income housing often benefit the most from energy-efficient structures, prompting companies to develop ideas for combining both while keeping rent affordable.

Fig. 12
figure 12

Low-cost rental green building apartment. Source: [33]

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One of the key benefits of green building practices is that they can reduce energy consumption and lower greenhouse gas emissions. This can help mitigate the effects of climate change while reducing the energy cost for low-income residents who may struggle to pay their bills. Examples of green building practices include using energy-efficient materials and appliances, designing buildings to utilise natural lighting and ventilation, and incorporating renewable energy sources such as solar panels or wind turbines [33]. Green building practices can also improve indoor air quality and promote healthier living environments for occupants. This is particularly important for low-income residents who may be more vulnerable to respiratory problems and other health issues associated with poor air quality. Examples of green building practices that can improve indoor air quality include using low-VOC (volatile organic compound) paints and materials, designing buildings to allow for good ventilation, and incorporating plants and green spaces into the building design [91]. However, the cost of implementing green building practices can be higher than traditional construction methods. This can make it difficult for low-income residents to access green housing options, particularly if they are not eligible for government or nonprofit assistance programs.

5 Discussion

5.1 Summary of findings

This study explored a spectrum of strategies aimed at providing sustainable and inclusive housing solutions for low-income families in Africa. Key findings indicate that mixed-use developments, incremental housing, low rental housing, inclusionary housing, 3D printing, upcycling, micro-housing, community-led housing, co-housing, and green building practices all hold potential as viable strategies to address housing challenges in urban African settings. It is important to note that the different housing strategies presented in this paper have both pros and cons (Table 1). Mixed-use Developments improve access to services, reduce transportation costs, and foster community interaction. However, they require significant land and infrastructure investments and can potentially lead to gentrification, displacing the very low-income residents they aim to help. Incremental housing is affordable and adaptable to residents' evolving needs, fostering a sense of ownership and community. However, its success depends on secure land tenure and basic infrastructure, and there can be challenges in financing incremental improvements. Low Rental Housing provides stable and affordable housing, reducing homelessness. However, it requires substantial upfront investments and ongoing maintenance costs, which can strain limited resources. Inclusionary housing promotes economic diversity and prevents displacement, improving health and well-being. Yet, it faces potential legal and political challenges and can reduce profitability for developers, making it less attractive in certain markets. The use of 3D printing reduces construction costs and time, promotes sustainability, and offers design flexibility. However, it is still a relatively new technology with limited capacity for large-scale production and potential regulatory barriers.

Table 1 Pros and cons of different strategies for sustainable innovative affordable housing (SIAH) for low-income families in Africa
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Upcycling reduces waste and lowers material costs, promoting environmental sustainability. However, it faces limitations in scalability and potential quality and safety concerns, which need to be addressed to ensure wider adoption. Micro-housing makes efficient use of land, is affordable, and has a lower environmental footprint. However, it may not provide adequate living space for larger families and can face cultural acceptance issues. Community-led and Co-housing models foster community engagement, enhance social capital, and promote shared resources. However, they require strong community organization and can experience conflicts over shared responsibilities. Green building practices improve energy efficiency, result in long-term cost savings, and reduce environmental impact. However, higher initial costs and the need for technical expertise can be barriers to widespread implementation. These strategies not only promote spatial justice but also contribute to the creation of inclusive, resilient, and sustainable urban environments.

In implementing the different strategies for sustainable innovative affordable housing for low-income families in Africa practitioners and policy makers should be aware of their pros and cons (Table 1).

The concept of spatial justice, as articulated by Soja [16], highlights the importance of equitable access to key resources and opportunities, particularly in urban settings. Our findings align with this perspective by demonstrating how innovative housing strategies can enhance access to affordable and safe housing for marginalized communities in Africa. For instance, mixed-use developments are shown to reduce transportation costs and improve access to essential services, thereby fostering spatial justice [42]. These developments integrate residential, commercial, and recreational spaces, promoting convenience and accessibility for low-income families. Whilst for the majority of the strategies presented in this paper, it is clear how they can contribute to spatial justice, it may also be beneficial to more explicitly state how strategies such as 3D printing and upcycling can contributed specifically to spatial justice. The ability to quickly construct homes through 3D printing in diverse and previously underserved locations means that more people can live in safe, adequate housing, thereby enhancing spatial justice. This means 3D technology can democratize housing by making it more affordable and accessible to low-income families. Converting unused or discarded materials into valuable housing resources, upcycling supports the equitable distribution of resources, promotes sustainable living environments, and reduces the socio-economic divide in urban areas, making homes more accessible to low-income families.

Sustainable housing strategies, such as 3D printing and upcycling, resonate with the literature on sustainable development [24, 25]. These methods not only lower construction costs but also reduce environmental impact, which is crucial in rapidly urbanizing African cities. For example, the use of 3D printing in constructing homes can reduce material waste and construction time, aligning with sustainable building practices that seek to minimize the environmental footprint [24, 25]. Incremental housing, which allows residents to progressively improve their homes as their financial situation allows, fosters a sense of ownership and community engagement, echoing the findings of Van Noorloos et al. [47] who emphasized the importance of flexibility in housing solutions for low-income populations.

The applicability of these strategies for sustainable innovative affordable housing within the African context is particularly pertinent given the unique socio-economic and environmental challenges faced by the continent. For example, mixed-use developments have been successfully implemented in Kibera, Nairobi, enhancing access to services and improving living conditions for residents [44]. Similarly, incremental housing projects like illustrate how such approaches can be adapted to provide affordable and flexible housing solutions in Africa [46]. In South Africa, the Cornubia Integrated Human Settlement exemplifies how inclusionary housing can provide affordable and sustainable homes for low-income families while fostering economic diversity and social inclusion [62]. This development integrates residential units with commercial and recreational spaces, offering a holistic approach to urban living that addresses both social and economic needs. Another example is the use of 3D printing in building affordable homes in Malawi. The 14Trees project uses this technology to construct homes rapidly, showcasing the feasibility and benefits of Modern Methods of Construction (MMC) in the African context [24]. Such methods can significantly reduce construction time and costs, making it possible to address housing shortages more efficiently. Community-led and co-housing initiatives, which are vital in communicating social housing strategies in South Africa emphasize the role of community participation in housing development, reflecting the principles of spatial justice and inclusivity. The success of community-led housing projects in South Africa demonstrates the importance of empowering residents to take an active role in the development and management of their living environments. The Makoko Floating School in Nigeria showcases the potential of using innovative building technologies in community-led projects. This school, built using locally sourced and sustainable materials, addresses the educational needs of the community while promoting environmental resilience. Similarly, the Freedom Park Co-Housing Project in South Africa demonstrates how co-housing can create affordable and sustainable living spaces by integrating communal resources and fostering social interaction. All these examples highlight the potential for tailored housing strategies to address the specific needs of African urban populations.

5.2 Integration of strategies for holistic solutions to low-income housing challenges

Addressing the complex challenges of low-income housing in African cities requires a comprehensive and integrated approach that combines various innovative and sustainable strategies. Leveraging the strengths of each method and mitigating their individual limitations, a more effective and holistic solution can be developed. Upcycling, which involves repurposing existing materials such as shipping containers and industrial scraps, can be seamlessly integrated with green building practices. Using upcycled materials inherently aligns with the principles of green construction by reducing waste and minimizing the environmental impact of housing projects. For instance, incorporating energy-efficient technologies and maximizing natural light and ventilation in upcycled structures can enhance their sustainability and livability. This combination not only reduces construction costs and environmental footprints but also promotes healthier living conditions for residents.

Micro-housing, with its emphasis on maximizing the use of limited space, can be effectively combined with co-housing models to create vibrant, socially cohesive communities. In a co-housing setup, multiple families share common spaces such as kitchens, gardens, and laundry facilities while maintaining their private living quarters. Integrating micro-housing units within co-housing communities can optimize space utilization and reduce overall living costs. This approach encourages social interaction and resource sharing, fostering a strong sense of community and mutual support among residents. Community-led housing projects, where residents collaborate to design and build their own homes, can benefit significantly from incorporating green building practices. Through involving community members in the planning and construction phases, sustainable building techniques such as using environmentally friendly materials and renewable energy sources can be implemented more effectively. This integration ensures that the homes are not only affordable and tailored to the residents' needs but also environmentally sustainable. Moreover, the participatory nature of community-led housing fosters a sense of ownership and responsibility, leading to better maintenance and longevity of the housing developments.

The rapid construction capabilities of 3D printing technology can be complemented by the cost-effectiveness and sustainability of upcycling. Using recycled materials in the 3D printing process, housing projects can benefit from both the speed and reduced costs of construction. This synergy can be particularly useful in addressing the urgent housing needs in urban areas, where time and resources are often limited. For example, 3D-printed houses made from upcycled plastic or concrete can provide quick and affordable housing solutions while minimizing environmental impact. Incremental housing, where homes are built in stages as resources become available, can also greatly benefit from green building practices. During each phase of construction, sustainable materials and energy-efficient technologies can be incorporated to enhance the overall sustainability of the housing units. This approach not only spreads out the financial burden for low-income families but also ensures that each addition to the home is designed with sustainability in mind. Integrating green building practices into incremental housing projects promotes long-term environmental and economic benefits for residents.

Combining co-housing with community-led housing approaches can create deeply integrated and supportive living environments. In this model, residents collectively design their shared living spaces, which can include common areas for social activities, childcare, and communal gardens. This integration fosters strong community bonds and enables residents to share responsibilities and resources. Working together, residents can ensure that their housing meets their specific needs while promoting social cohesion and economic inclusion.

5.3 Policy implications and future directions

The findings of this study highlight the need for policies that support the implementation of innovative housing strategies. Governments and stakeholders should prioritize the provision of land and infrastructure, ensuring that these foundational elements are in place to support housing development for low-income families. Additionally, innovative financing models need to be developed to make housing projects financially viable, especially for low-income populations. Regulatory frameworks should be created to facilitate the adoption of Modern Methods of Construction and sustainable practices. This includes revising building codes and regulations to accommodate new technologies like 3D printing. Furthermore, promoting community engagement is essential to ensure that housing solutions meet the needs and preferences of residents, fostering a sense of ownership and long-term sustainability.

Overall, addressing the housing challenges in Africa requires a holistic approach that incorporates spatial justice principles and sustainablity practices. Leveraging the diverse strategies discussed in this paper, African cities can create inclusive, resilient, and sustainable urban environments for low-income families. The integration of these strategies can lead to more effective solutions, ultimately contributing to improved living conditions and greater social equity across the continent.

6 Conclusion

This paper explored a range of innovative and sustainable housing strategies aimed at addressing the housing challenges faced by low-income families in Africa. Each strategy offers unique benefits and presents specific challenges, contributing valuable insights to the discourse on sustainable housing. Through examining upcycling, micro-housing, community-led housing, co-housing, green building practices, and 3D printing, the paper provided a comprehensive analysis of how these methods can be implemented to create affordable, sustainable housing solutions. The strategies discussed in this paper are interconnected and can be combined to create more comprehensive housing solutions. For example, mixed-use developments can incorporate green building practices to enhance sustainability, providing environmentally friendly and economically viable housing options. Similarly, incremental housing can benefit from upcycling materials, which reduces costs and environmental impact while allowing for gradual home improvements. Community-led housing initiatives can integrate co-housing principles, promoting social cohesion and shared resources, which are crucial for building resilient communities. These interrelationships highlight the importance of a holistic approach to housing development, where multiple strategies are employed in tandem to address the diverse needs of low-income urban populations. Leveraging the strengths of each strategy, policymakers and developers can create more effective and sustainable housing solutions.

This article's primary contribution to knowledge lies in its detailed analysis of various sustainable housing strategies and their applicability within the African context; also demonstrating that there is no one-size-fits-all solution to the housing crisis in Africa. Highlighting the practical benefits and challenges associated with each strategy, the study provides a valuable resource for policymakers, urban planners, academics and housing advocates. The comparative analysis of these strategies offers a nuanced understanding of how different methods can be leveraged to address the complex housing needs of low-income populations in Africa, promoting both social justice and environmental sustainability.

Based on the findings of this paper, several recommendations can be made:

  • Policy Support: Governments should create supportive regulatory frameworks to facilitate the adoption of innovative housing strategies, particularly in urban areas.

  • Public–Private Partnerships: Collaboration between the public and private sectors can provide the necessary financial and technical support for large-scale implementation of these strategies.

  • Community Engagement: Actively involving communities in the planning and development process can enhance the acceptance and success of housing projects.

  • Financial Incentives: Subsidies and financial assistance programs can help offset the higher initial costs of green building practices and other innovative construction methods.

  • Capacity Building: Training programs for local builders and artisans can improve the quality and safety of upcycled and 3D-printed housing.

While this study makes a valuable contribution in the field of low-income housing in Africa some limitations can be highlighted. First, the analysis is largely conceptual and would benefit from more empirical data to validate the findings. Second, the study focuses on selected key strategies and does not explore other potential solutions that could be relevant in different contexts. Future research should address these gaps by conducting case studies and pilot projects to gather empirical evidence on the effectiveness of these strategies in various African settings. Additionally, exploring the socio-cultural dynamics that influence the acceptance of innovative housing solutions would provide deeper insights into their practical implementation. Future research could also delineate the strategies into distinct categories based on their nature and purpose (strategy, method/tool, practice etc.), providing a clearer framework for understanding and implementation.

In conclusion, this study highlights the potential of innovative and sustainable housing strategies to address the housing challenges faced by low-income families in Africa. These strategies can create affordable, sustainable, and socially inclusive housing, significantly enhancing the quality of life for millions. The study demonstrates that these strategies are vital for sustainability and spatial justice, necessitating a comprehensive approach that integrates social, economic, and environmental dimensions of urban development. Promoting sustainable and equitable urban development is essential for creating healthier, more resilient, and inclusive cities. The paper calls on policymakers, practitioners, and academics to prioritize low-income housing in Africa, advocating for a holistic approach that ensures access to secure, affordable housing, fostering cities that are inclusive, equitable, and sustainable for all.