Building resilient homes in informal settlements

Understanding access to building materials in Freetown and Harare

Rows of grey bricks on the ground outside a house. In the background, washing is hanging on a line.

Block making in Dzivarasekwa, suburb of western Harare in Zimbabwe (Photo: Marcelle Mardon, IIED)

A resident of Colbot, an informal settlement in the coastal area of Freetown, Sierra Leone, has just made some improvements to his house. While he paid a supplier Le 400 (around US$20) for a small truck full of sand, including the transportation costs, it was delivered only as far as the entrance of his community. 

His house is around a mile from the community entrance. He says: “Consequently, I need to compensate a community worker with an extra fee of Le 200 to transport it to my site, resulting in a total cost of Le 600”. This is 50% more expensive than what someone who lives outside the informal settlement would pay for the same amount of sand delivered to their house.

The vital role of building materials in informal settlements 

Informal settlement dwellers are constantly investing in incrementally improving their housing. Accessing building materials that are affordable and resilient is a key priority for most informal settlement households. Construction materials are used to build and maintain homes and can also play a crucial role in improving livelihoods and other development outcomes, as well as supporting adaptation efforts in the face of increased climate-induced events such as flooding and extreme heat.

A huge landslide on the side of a hill, with small houses just beneath it.

A good example of climate-induced events is the series of mudslides in Freetown, Sierra Leone in August 2017, following three days of torrential rain, that killed 1,141 people and left over 3,000 homeless (Photo: Mark Stedman/Trocaire, via Wikimedia Commons, CC BY 2.0 Deed)

Ensuring access to affordable and sustainable materials for housing in informal settlements is a key condition for implementing global commitments such as the UN-Habitat Resolution on Accelerating Transformation of Informal Settlements and Slums and the Ministerial Declaration of the Buildings and Climate Global Forum (PDF)

Even though wealthier countries and societies are responsible for most emissions propelling climate change, informal settlement residents carry the burden and impacts of environmental degradation disproportionately. This calls for finding responses that advance efforts for local adaptation to increase resilience while also acknowledging and contributing to wider efforts for decarbonisation – namely, the efforts to remove or reduce the amount of carbon dioxide put into the atmosphere by transitioning to energy sources with low-carbon emissions. 

The challenge of ensuring just urban transitions for informal settlement upgrading (PDF) is becoming a central issue. As a testament to such attention, the global partnership the Cities Alliance, in collaboration with IIED’s team working on this issue, has mobilised efforts to understand to what extent the urban poor can afford to be sustainable (PDF).

Understanding access  

Despite the importance of building materials, there is little knowledge about what incentives, norms or regulations shape access to building materials used for housing in informal settlements. In other words, what conditions enable or constrain the value chain of these materials (from extraction, transport and assembly, to construction, use and reuse), and how these conditions make housing construction more affordable and sustainable. There is also a poor understanding of the multiple cultural, economic, social, legal and environmental systems that are intertwined in such value chains.

IIED has been working for the last few months with Slum Dwellers International (SDI) affiliates in Harare (Dialogue on Shelter) and Freetown (Centre of Dialogue on Human Settlement and Poverty Alleviation, CODOHSAPA) to investigate the governance (namely, the incentives, norms or regulations exerted by different actors) of the value chain of building materials used for housing in informal settlements in both cities.

A small shed with piles of gravel and sand outside. On a motorbike, sheets of corrugated iron.

Sand, gravel and rock are stored at a Freetown construction site (Photo: Camila Cociña, IIED)

IIED’s Housing Justice team co-developed a methodology with Dialogue on Shelter and CODOHSAPA to find out how people access construction materials. We selected strategic materials used for housing in two informal settlements in each city. Working together with informal settlement residents who are members of federations of the urban poor in each city, we then identified and interviewed extractors, producers, transporters, suppliers, builders and users in the value chain of these materials. Most interviews were conducted by federation members, who also produced videos with members of SDI’s Know Your City-TV initiative. Together, we aimed to investigate:

  • What are the barriers and incentives for the supply and use of pro-poor climate-resilient materials in informal settlements? 
  • What kinds of risks, burdens and injustices are embedded in their value chain?, and
  • What are the opportunities and entry points to address these injustices and advance resilience?

In this long read we share some of the reflections, findings and lessons that have emerged from this collaboration in Harare and Freetown. Our efforts have been aligned with the ongoing initiative Roof Over Our Headd (ROOH), led by the Indian NGO SPARC. ROOH is a campaign focused on delivering resilient, low-carbon and affordable homes for those living and working in informality. Our process was also nurtured by a series of engagements, such as an online multi-stakeholder workshop in January 2024 with key actors from multilateral agencies, NGOs, researchers and local partners.

An illustration showing discussion points from a workshop about building materials for informal settlements.

This illustration shows the discussion about building materials for informal settlements among participants at a workshop in January 2024 (Illustration: Katie Chappell/IIED)

Coping with climate change: building materials matter

Worldwide, the construction sector is a key contributor to climate change and environmental degradation. Buildings are responsible for 39% of global carbon emissions (including construction and operational emissions), and current trends leave the construction sector off-track for reaching the goal of decarbonising by 2050. Concrete alone is expected to contribute 12% of global greenhouse gas emissions in 2060. In 2018, housing and infrastructure represented the societal need with the largest resource footprint globally, using around 50% of the resources extracted annually.

The demand for building materials is growing rapidly in cities of the global South, particularly in sub-Saharan African cities. Large-scale companies extracting, producing and distributing building materials such as cement have unprecedented levels of profits in the region. Their production model has led to the unsustainable extraction of resources such as sand and stone, as well as deforestation, resource depletion, destruction of ecosystems and the reduction of countries’ resilience to current and future environmental impacts. Locally-sourced and more sustainable building materials have often not received the same levels of incentives, making them less desirable and competitive in local markets.

At the same time, building materials and techniques play a crucial role in influencing the capacity of communities to adapt to climate change and improve their resilience, as well as supporting local livelihood opportunities and cultural practices

Accessing affordable and robust building materials is a key concern for informal settlement dwellers, particularly as poor households tend to pay high costs for goods – above their market value – due to what has been termed the “poverty penalty”. Recent studies have shown that informal settlement households in African cities can spend 15-30% of their monthly budget on materials for repairs and improvements, which is particularly challenging considering issues of inflation and the macroeconomic fragility affecting many countries.

Residents of informal settlements experience a series of unfair burdens associated with the access and use of building materials. They are exposed to building materials that are often fragile, not climate-resilient, unaffordable and at times toxic. Often, those burdens are shaped by decisions made very far from the settlements, either at the national or international level. 

Given the projected growth of informal settlements in sub-Saharan African cities, access to resilient, safe and affordable building materials is a necessity to advance housing justice and to promote local strategies to meet Sustainable Development Goal target 11.1, which seeks to “ensure access for all to adequate, safe and affordable housing and basic services, and upgrading slums”.

Exploring the complex value chains of bricks, sand and roofing sheets

In Harare and Freetown, we enquired how informal settlements’ residents access building materials and how the local context influenced their capacity to build safer and more resilient houses.

Focus on Harare, Zimbabwe

In Harare, the research focused on two settlements. Dzivarasekwa Fedland started as a temporary solution in 1991 and currently hosts more than 5,700 residents and is in the process of land tenure regularisation. It is in an area of high winds and is prone to flooding. The second settlement, Tafara Fedland, was established as part of a slum upgrading programme in 2017 and is still pending legal recognition and the granting of land tenure to residents. It is in a sandy soil area, prone to flooding and high winds. 

We worked with local partners to focus on two materials: bricks and roofing sheets. Residents typically use farm bricks and homemade cement bricks to construct walls and partitions in Tafara. These are a cheaper alternative to the burnt clay brick and ‘well-made’ cement bricks found in Dzivarasekwa, where permissions are in place for the construction of more permanent dwellings. 

Similarly, Tafara communities have opted to invest in lightweight roofing materials. They use lower gauges (typically 0.18mm) of corrugated iron roofing materials, which are cheaper, more easily-transported and repaired. In more permanent homes, as in Dzivarasekwa, residents typically use a higher gauge of 0.4 mm, keeping in line with building standards recommendations. In both settlements, some homes are roofed with more expensive asbestos sheets (sometimes recycled, as in Tafara), a more desirable material with a reputation of being robust, offering a higher level of thermal comfort and approved by building standards.

People from two informal settlements in Harare discuss the choices and challenges around the building materials used to construct or maintain their homes (Video: KYCTV)

Unlocking the value chain: bricks and roofing sheets

The value chain of these building materials (illustrated in the animation below) is complex and difficult to capture in a simple linear description. Farm bricks are sourced from local brick moulders, in the case of Tafara, from the nearby Chishawasha area, less than 5km away. They are fabricated using locally available anthill soil (which has a high silica content) and strengthened with rubble coal and waste from larger industries in the neighbourhood of Msasa. Temporary labourers are hired for digging, moulding and loading the bricks into trucks, an informal part of the value chain where non-standardised wages are constantly prone to disputes, adding to lower profit margins or passing on as increased prices to homeowners.

A man stands in front of a pile of clay.

Clay brick making in Harare (Photo: Marcelle Mardon, IIED)

On the other hand, the standard burnt clay bricks used in Dzivarasekwa are sourced from local (indigenous) or foreign-owned brickmaking plants. Residents mainly opt to buy from the latter suppliers due to their cheaper prices, good quality and being subject to industrial tests and checks. Chinese-owned manufacturers have access to more modern brickmaking machinery and kilns, giving them an edge over their local counterparts. The raw material is extracted from large open pits near plants, and the coal is transported from the country's coal mining area, which is more than 500km away. 

The study highlighted that negotiated payment schemes offered by foreign-owned brick manufacturers permitted collective bulk buying of material for more vulnerable communities and, in turn, reduced transportation costs, further adding to the advantage of buying from them.

Cement bricks, which are considered a more robust option than ‘burnt’ bricks, are often made on-site, either by local artisan builders or by household members themselves. The quality varies greatly and depends on the proportions of cement (usually sourced from China) and local river sand and aggregates. The more permanent homes in Dzivarasekwa had a higher proportion of cement than those in Tafara, where residents complained of heavy rains percolating through the bricks and causing damp.

With regards to metal roofing, finished cut or rolled sheets arrive from China at ports in neighbouring countries, and local Zimbabwean importers bear the heavy costs of transporting them to landlocked Zimbabwe. Metal roofing sheets make their way to the markets in the city centre of Harare, such as the home-industry site Siyaso Mbare. They are transported in smaller quantities to smaller local retailers, such as Gazebo, located near both settlements. Smaller retailers must accept small repeated transactions adjusted to the limited capacities of residents and find strategies to balance the risks of overstocking or shortages of essential materials.

Finally, asbestos sheets, commonly used in low-cost housing because of Zimbabwe’s long-standing asbestos mining industry, are now an imported raw material from Brazil and Russia. Despite serious health and safety implications for people handling asbestos, from producers to users, the material remains a much desired and preferred choice.

Transportation is mainly provided by community members hired by homeowners. Vehicles are often unroadworthy, without lights or horns and are characteristically customised to accommodate heavy loads. Costs average $20-30 per 1,000 bricks, plus a cost for transport based on distances covered. The prices are negotiated but increase with any additional extras, such as covering the materials from the elements. Transport challenges are more acute due to the condition of the road network. A builder and resident member of the federation of the urban poor in Dzivarasekwa Fedland says: “Government needs to intervene on price control of transportation charges and ensure roads are repaired.”

The poor state of roads also complicates the safe delivery of materials prone to breakage, including bricks and the more fragile asbestos sheeting. As a result, deliveries are made to the entrance of sites, as in Tafara, where residents must pay for someone to wheelbarrow them to homes, potentially losing bricks to theft along the way. Transporting materials under the cover of night is a common strategy to cut costs related to insurance and road taxes. Loaders are also employed along the value chain, with residents absorbing these additional costs.

Interior of a house showing asbestos sheeting has been used as a building material.

Asbestos material for sheeting, imported from Brazil and Russia, is often used for roofing in Harare (Photo: Marcelle Mardon, IIED)

In terms of corrugated iron sheets for roofing, Tafara homeowners buying from Gazebo, located about 5km away, tend to be women who avoid transportation costs by buying single sheets and carrying them on their heads despite the cuts to their hands and faces from handling the fragile material.

The decision to employ professional or untrained builders/artisans is often a question of affordability versus quality. In turn, artisans must absorb the costs of inflation-prone materials in a highly competitive space where price negotiation is unavoidable. With low profit margins, it is common to find them making shortcuts. 

Building regulations, which specify minimum standards for construction, are not enforced in Tafara because of its tenure status. As a result, builders have the final say over the ratio of sand to mortar. A common result of this compromise is homeowners paying the price with porous bricks and water entering homes in rainy seasons, roof leaks and tears, all contributing to respiratory issues. 

Because the regularisation process has been initiated, builders in Dzivarasekwa must be qualified and pay high licensing costs. Builders compensate for these costs by working with unqualified assistants on very low wages. Regular inspections present incentives to work to good standards; nevertheless, there are instances of corruption that see substandard work approved. The burden ultimately falls on the residents who, in the case of Dzivarasekwa, must build their homes with certified materials with very little or no support, due to the lack of more pro-poor regulations that recognise and address the economic difficulties of many residents.

An animation showing the value chain of bricks and roofing sheets used for homes in informal settlements in Freetown, Sierra Leone, focusing on the communities of Colbot and Moyiba (Video: Lowii Studio/IIED)

Focus on Freetown, Sierra Leone

Research findings in Freetown, Sierra Leone, echo our findings in Harare. The work led by CODOHSAPA and the Federation of the Urban and Rural Poor (FEDURP) focused on the settlements of Colbot and Moyiba. 

Colbot is a coastal settlement housing more than 11,000 people, prone to regular flooding, given that it is partly built on land reclaimed from the sea. Some residents undertake gravel collection from rainwater channels. It is also a settlement where many households are going through a process of consolidation of their housing structures, moving from light corrugated iron structures to more solid concrete houses. 

People standing outside a corrugated iron house.

Corrugated iron sheets are used to make this house in Freetown, Sierra Leone (Photo: Camila Cociña, IIED)

Moyiba is a settlement of similar size located on the hillside of Freetown which was initially built decades ago around livelihoods related to a granite quarry. Due to the geography of the hill and minimal infrastructure investment, Moyiba has very poor road connections and relies on motorcycles and walking to access the community. Over the last few years, it has faced an increasing number of mudslides due to heavy rains.

Our research in Freetown focused on the use of and access to two materials: sand and corrugated iron sheets (illustrated in the animation below). Sand is a fundamental and desired material for housing improvements, including floors, walls, containment barriers and the finishing of indoor and outdoor surfaces. When combined with cement, water and occasionally gravel and stone, it is used as a material for consolidating housing structures as a key step to move towards tenure regularisation. Extracted both from local beaches and provinces, it comes in different qualities: salty-water sand (cheaper, but less durable), fresh-water sand (preferable but more expensive), and mud sand (Baghdad sand), as well as a mix of sand with gravel, which acts as a substitute for sand.

Corrugated iron, on the other hand, is a crucial material for temporary solutions throughout buildings, used mainly by residents who are unable to afford bricks, mortar or cement, or by those not willing to invest in more expensive materials due to uncertainties about tenure. When paired with other materials, it is also used for more permanent and desirable roofing solutions. Its quality varies greatly, but the most commonly used is the cheap 6ft (1.8m) sheet (‘Five-star’ brand), which tends to be ill-suited for heat, flooding and other climate hazards and needs constant replacing due to its poor quality. Likewise, households often recycle old pieces of sheeting to cover parts of their houses, either buying them very cheaply or recovering them for free.

Unlocking the value chain: sand and corrugated iron sheets

Sand is mined from areas such as Lungi, Koya Mabendu and Loko-Masama chiefdom. To mine the sand, sand miners travel by boat from Freetown to waterfront villages and communities in the country’s interior. Sand-mining communities such as Fishery have locally-run companies managed by community chiefs that operate with well-established by-laws and regulations. They employ local men to work as miners in a job that requires huge physical work and exposure to several health hazards related to skin exposure to salty water, lifting heavy weights and often dangerous sailing conditions. 

A large boat at a jetty, with several people in it.

Sand miners travel by boat from Freetown to waterfront villages and communities (Photo: Camila Cociña, IIED)

After it is extracted, the sand is deposited in local Freetown suppliers’ fields, which become a hub for other activities such as food selling and transport. Community members from Colbot and Moyiba reported that they got sand from suppliers that were chosen mainly due to proximity to each community, such as Bottom Oku Wharf, Fishery sand ground and Kaninkay Wharf.

Transport cost is a key determinant of the sand price and is usually outsourced to independent transport companies. These companies usually transport only to the entrance of informal settlements, relying on local community members for transporting materials to the building site. Actually, people in Moyiba, which is located on a hillside, purchase sand at a higher price than those in the coastal settlement of Colbot, closer to the sand suppliers’ fields. 

Transport costs also determine prices for suppliers: fresh-water sand is more durable, safe and smooth than salty-water sand, but its high price is mainly due to the longer distance to the extraction sites, the fuel required, and the level of risks involved in its extraction from fresh water.

Men standing among large piles of sand. Concrete sheds behind them.

A supplier's sand field in Freetown. These become hubs for other activities such as food selling and transport (Photo: Camila Cociña, IIED)

In Colbot, gravel is usually collected, put into bags (using ‘lots’ as local units) and transported to construction sites in the community by youths hired by residents. Non-filtered, semi-filtered and well-filtered gravel varies in quality and price. Gravel collection takes place in water channels next to the settlement, usually following heavy rains, and it is a highly unregulated process that exposes those collecting gravel (usually young boys) to numerous risks. 

Evidence collected suggests that residents have received contradictory signals from the government concerning these practices: on the one hand, it actively seeks alternative livelihood options to discourage stone mining; while on the other, government disaster agencies encourage gravel collection as a preventive measure against flooding.

A large ditch with corrugated iron buildings on both sides.

A water channel close to a Freetown informal settlement where gravel collection typically takes place, often after heavy rainfall (Photo: Camila Cociña, IIED)

Corrugated iron sheets tend to be imported from China. They are shipped to Freetown Port and, after getting clearance from port authorities, are delivered to small and large suppliers and shops, where residents of informal settlements buy them. Transporting corrugated iron sheets into communities is also challenging. They are usually transported to the construction sites via motorcycle (Okada) or pushcart (Omolanke), because of the poor or nonexistent roads. This form of transportation increases the costs paid by homeowners and limits the volume that households can buy at once.

Construction tends to be done by builders who are community members. Some households hire small construction companies established by local builders with groups of assistants, while other households build their homes themselves, working with relatives who have taught themselves building techniques. 

As in Harare, households constantly assess the risks and costs of hiring builders with different levels of skills. A resident from Moyiba, for instance, describes how his siblings did most of the construction of his house – but he paid someone else to fabricate the blocks outside of his house to ensure better quality.

Several other factors shape the challenges facing people living in informal settlements who want to access affordable and sustainable materials. Inflation and macro-economic fragility are crucial factors, with interviewees reporting prices of some components changing up to five times in two years. 

Lack of affordability encourages households to opt for cheaper options even if they are of worse quality and less suited for environmental conditions. In the long run, this implies constantly renewing materials damaged by climate-induced hazards. 

Often, land tenure insecurity is a significant factor, as some residents prefer to use cheap materials such as corrugated iron sheets because they fear eviction, even if they are aware of the downside of using them in terms of climate performance and durability. Sierra Leone regulations are not particularly pro-poor in supporting locally produced and accessible materials. This is partly due to the lack of supply and management systems that ensure affordability and accessibility.

An animation showing the value chain of bricks, sand and corrugated iron sheets used for homes in informal settlements in Freetown, Sierra Leone, focusing on the communities of Colbot and Moyiba (Video: Lowii Studio/IIED)

Four lessons to shape policy

The stories we collected through this initiative reveal the importance of understanding the multiple systems that shape the value chain of building materials in informal settlements.

Recognising that building materials value chains intersect with several social, economic, political and environmental systems can unveil innovative entry points for effecting change, going beyond traditional entry points that might reinforce the status quo. Our research in Harare and Freetown reveals the multiple actors and processes that intersect in the effort to access and use building materials. These actors and processes relate to livelihoods, culture, hazards, gender, infrastructure, legal frameworks and fuel prices, among several other issues.

While acknowledging these systems, we identify four key aspects that national and local governments need to consider when designing policy responses or interventions:

1. The complexity of livelihoods alongside the value chain

Countless people depend on livelihoods that take place alongside the extraction, processing, transporting, selling, storing and assembling of building materials in informal settlements. Drivers, sailors, miners, rock-breakers, vendors, site managers, truck and motorcycle owners, constructors, food suppliers and a long list of occupations feed into the materials’ value chain. People’s livelihoods linked to these value chains range from more or less formalised jobs with different degrees of safety and security. They are linked to complex processes that are dependent on fuel prices, government restrictions, extreme climate events or inflation. These occupations and their degree of fragility are also informed by issues such as age, gender or ability, with certain roles usually fulfilled by young boys or women. 

Any interventions to the value chain of building materials that governments implement must consider the importance of secure livelihoods, strengthening rather than weakening people’s ability to secure certain living standards. Likewise, recognising and addressing the health hazards that some of these occupations entail must be a central criterion for interventions.

A boat on a jetty, with food supplies on the ground.

Boats for sand mining and food supply in Freetown. Many people depend on livelihoods that take place alongside the transporting of building materials (Photo: Camila Cociña, IIED)

2. Tenure security and risk thresholds

Different degrees of tenure security is a key feature of informal settlements. Household decision-making around building materials is intrinsically connected to tenure security. Sometimes, residents might decide to use cheaper and less durable materials such as corrugated iron sheets because they fear imminent eviction. As a resident and builder in Tafara notes: “Local authorities need to approve planning permissions so communities can move from temporary to permanent housing construction.”

In other cases, investing in more durable materials such as bricks or cement is seen as a strategy or a step to exercise pressure for regularisation, even at the risk of losing the investment if an eviction happens. Likewise, decisions about investing are shaped by the urgent need to implement adaptation strategies in areas prone to flooding or other hazards, even if this might be a temporary solution. These decisions and the tolerance to uncertainty and risks are also informed by tenure status, with tenants usually having very little power against landlords operating in extremely unregulated conditions.

Governments’ interventions must recognise that advancing security of tenure is at the core of promoting a fairer and more sustainable use of building materials in informal settlements. Policies and regulations that promote the affordability of sustainable materials are likely to remain irrelevant for those experiencing uncertain tenure. These challenges must be addressed side by side, acknowledging the complexity of the continuum of land rights.

3. Fairer distribution of climate change burdens and responsibilities

Poor communities and residents of informal settlements do not bear the main responsibility for climate change. They are, however, encountering most of its consequences daily. Decisions around ‘durable’ and ‘strong’ materials are shaped by their experiences of periodic floodings, storms and extreme heat, as well as mudslides and other extreme events.

The tension between burdens and responsibilities is clearly reflected, for example, in the use of concrete. Cement, a building material with an enormous global environmental footprint, is paradoxically a crucial asset for building structures resistant to climate-induced events in informal settlements. Concrete also has important cultural significance and is a symbol of status and permanence in many countries. For example, a resident of Colbot in Freetown describes how “corrugated iron sheet houses are systematically fading away because people want to construct concrete houses” as they want more durable and culturally adequate solutions. Cement is, therefore, often seen as a robust and desirable alternative. 

This house is not sturdy and is unsuitable for the current climate conditions. The zinc, upon contact with salt water, rusts over time, creating holes through which water seeps, resulting in frequent house flooding.

Colbot resident

Any interventions and regulations enforced by the authorities must consider the importance of reducing the vulnerability of people bearing the burdens of climate change vis-a-vis the need to decarbonise the global building materials sector by reducing its carbon emissions. Interventions in the value chain must consider the cultural dimension of materials and the immediate impact the use of certain materials might have on communities’ resilience and adaptation efforts.

4. Governance over technology solutions

Global calls for using greener and more sustainable materials need to consider the reality of informal settlement communities. Ensuring affordable and sustainable materials involves more than developing adequate technological solutions; it is mainly about transforming the governance, incentives, regulations, markets and spaces of decision-making around building materials. Promoting affordability needs to be at the centre of this question, recognising the ‘poverty penalties’ that settlement households usually pay, alongside the issues of livelihoods, security of tenure and cultural uptake discussed above. 

Often, successful stories about sustainable building materials in informal settlements are related to the capacity of organised communities to access and store materials in collective ways or to the increased power that collective bargaining brings with providers, builders or authorities. 

Interventions must consider the trade-offs that planning instruments, construction codes, economic incentives, taxes and other systems imply. Safeguarding building materials’ affordability and access, while protecting safe livelihoods and increasing resilience, requires carefully looking at the unintended consequences of interventions. 

Strengthening organised communities in informal settlements and their capacities to assess their needs and act collectively should be a key priority for policymakers, as solutions will only be truly sustainable if they are locally led through an empowering process that increases residents’ collective capacities.

This is, ultimately, a question of governance, decision-making and an enabling environment that supports such efforts.

These four lessons aim to promote interventions that favour access to affordable and sustainable building materials in informal settlements without ignoring the complexity that sustains them. This implies safeguarding the safety, security and livelihoods of those interacting with their value chain.

Overall, these lessons are a call for enhancing the ability of civil society and grassroots groups to promote construction processes in informal settlements that are more equitable and sustainable. These processes, in turn, can promote housing justice by addressing the discriminations that informal settlement dwellers experience, recognising collective democratic processes, and tackling climate injustices.

We also hope these lessons can open more research and action initiatives that unveil local and global flows of materials, revealing how decisions and frameworks at different scales impact the distribution and access of resilient building materials and housing conditions.