Core housing programmes government schemes which provide a service unit that residents can themselves extend were a common way in which intragovernmental organisations funded social housing in the postwar period in the global southCredit:Greg Marinovich / South Photos / african.picturesMasterplans have been tools of elite control for more than a century. They stand in stark contrast to the intensely local constructions and urban transformations built by residents themselves. Even at the peak of their influence, masterplanners such as Daniel Burnham or Le Corbusier were hardly oblivious to the ways their work exerted power through design, nor did they miss the potential for explosive conflict. When Le Corbusier described a choice between architecture or revolution in 1920, for instance, he was clearly warning other architects that only adequate modern housing could quell social unrest.Throughout the 20th century, and particularly after 1945, urban dwellers divided into those whose needs were adequately met by formal buildings, and those whose needs were not. The latter category made do by constructing their own houses near workplaces and by hooking up their own electrical lines, setting up their own security systems, and otherwise figuring out how to shelter themselves near work sites. They were architects of an ad hoc urbanism born out of necessity. The self-built settlements, or barriadas, surrounding Lima share some structural functions with the panjachons of post1953 South Korea or the deliberately underserviced Kibera area, both during and after British colonial control, in the city of Nairobi. This kind of selfhelp activity is the most important way in which cities have grown in the last 80 years.Within the world of planning and architecture, there were a few individuals who led the charge away from masterplans for international organisations and development programmes. Three itinerant advisers Jacob Crane, Charles Abrams and John FC Turner championed a new kind of incremental, peopledriven architecture. Beginning in the 1950s and accelerating through the following two decades, all three rejected the idea that socalled slums could be wiped away and shiny modern housing put in their place. Instead, they contemplated how international funding might support and improve peoples efforts on the ground. As Turner wrote in his 1976 book Housing by People: Towards Autonomy in Building Environments: Only a rich minority can be supplied in centrally administered ways using centralising technologies, and then only at the expense of an impoverished majority and the rapid exhaustion or poisoning of the planets resources.Based on such ideas, the United Nations conducted experiments with the notion of aided selfhelp housing in the postwar years, testing homes that were a combination of governmental and/or intergovernmental assistance and resident effort. In essence, aided selfhelp experiments built standard cores constituting a minimum liveable housing unit and then encouraged residents to build out the structure. This process incorporated the benefits of fast, massconstructed cores with the lower cost of selfhelp improvements and adaptations. There were many variations of this concept, including programmes that only offered basic services such as water lines and a foundation along with floor plans for eventual construction; governmentsponsored equipment and loans for materials; a concurrent development of local building material industries and a training programme; and mass construction of basic houses with detailed suggestions for how to expand.The March 1962 pilot programme in Tanganyika a recently decolonised nation that achieved independence in December 1961, and would eventually join with Zanzibar to become Tanzania in 1964 offers a window into these early schemes. Prime Minister Julius Nyerere had just assumed office, and a few months later, the UN worked with Nyerere, Nyereres cabinet and the Tanganyika African National Union (TANU) to launch a threephase programme on Morogoro Road in Magomeni, a ward in central Dar es Salaam. The planned first phase was a governmentled effort, with 10 houses constructed from March 1962 to April 1963 by the new nations Public Works Division, using a basic model that included a kitchen and latrine. The second phase starting in May 1963, meanwhile, attempted more complex improvements for another 10 houses. This second phase was to be led by homeowners and supplemented by voluntary labourers organised by TANU. Improvements included corrugated aluminium roofing for some houses and corrugated asbestos cement sheets for others, as well as cement plaster, Celotex fibreboard ceiling panels, concrete floors, electrical lighting, iron pipes and proper outbuildings with septic tanks. Because most of these building materials (minus the soil-cement blocks) needed to be purchased and brought in, homeowners would be required to repay material costs at 57 per cent interest over five to 10 years. The third phase had the least structure of all three: in this last phase, the UN and government envisioned only providing technical supervision while groups of residents built their own homes. No number of houses was detailed for the third phase, and it appears none were formally built or tracked by the UN.More than 500 unskilled volunteers contributed to the pilot programme, but skilled labourers also had to be hired, and expensive building supplies purchased. This limited the number of people who could ultimately afford the improved units. And the government was so fully involved that the lead UN housing expert, Jorge Arrigone, speculated that the housing programme could not accurately be described as selfhelp at all. In the end, the scheme did not have a huge impact on the housing crisis in Dar es Salaam; the city and the new nation struggled to house urban dwellers, and the core housing model never became the predominant form of housing construction there. The houses constructed in the first two phases disappeared in successive waves of clearance and rebuilding, and the UN paper trail goes cold on the third phase. Yet the concept of modern core and selfbuilt extension persisted in successive attempts around the world by the UN and other aid organisations and soon, by international banks too.The housing that planners imagined would most empower residents, by encouraging them to add extensions, made people feel disconnected from the cityIt took some time for the World Bank to join in the effort to improve housing at the international level, but when it did, it incorporated many of the ideas tested by earlier selfhelp proponents. Itself another product of the reconstruction efforts following the Second World War, the World Bank turned decisively to the problem of urban poverty in the 1970s in large part because of the leadership of former US secretary of defence Robert McNamara, who served as the organisations president for the entirety of that decade. The World Bank focused on two strategies: sites and services and squatter upgrading.Squatter upgrading programmes attempted to improve lowincome, highdensity urban neighbourhoods through the installation of roads, sewage, water, schools and other community resources. Upgrading emphasised the rationalisation of roads and services, and although the name suggested that residents would stay, plans often involved substantial removal and clearance. For instance, when the World Bank wanted to straighten and widen main roads in the dense settlement of Tondo in Manila, it had to dedensify or reduce the number of families living in the path of the anticipated road.Sites and services, meanwhile, also emphasised the installation of basic amenities, but in locations that were not yet developed and that were often further from dense urban cores. The logic was that as newcomers to cities became familiar with the urban landscape and achieved some income stability, they might want to move out of a crowded self-built neighbourhood into better, perhaps formal housing. Even with a stable income, however, the newly urbanised family might not be able to afford an actual apartment or a city house. In this instance, the World Bank hypothesised that this kind of family might be happy to move to a house in a slightly more distant location in order to trade up in building quality. In theory, a sites and services home would provide a core for water, sewage and other services, while giving residents the freedom to build extra rooms or amenities as they continued to make money.Imelda Marcos and Robert Macnamara at the loan signing ceremony for a World Bank core housing pilot project in the Philippines. This scheme was widely regarded as a failure, though the overall concept of extendable core housing is now being re-evaluatedCredit:World Bank Group / Edwin G Huffman In Manila in the late 1970s, the World Bank funded squatter upgrading in central settlements, starting with Tondo. Sited north of Intramuros, the old Spanish centre of town, and hugging Manila Bay, Tondo was arguably Manilas most famous selfbuilt settlement. Populated in waves for centuries, the dense urban centre became impoverished in the decades after the Second World War because rural inmigration was fierce, and because years of war and colonisation had devastated urban amenities in the region. By 1974, Tondo had evolved into a critical site for redevelopment, as the World Bank officials and Philippine presidentturneddictator Ferdinand Marcos and his wife Imelda looked for ways to open access to the port and harbour via Radial Route 10. Together, they agreed that upgrading should bring physical order to a community that appeared like an embarrassing eyesore a crowded jumble of housing units to outsiders. Those residents who had to be displaced to make room for widened, straightened roads and easier access to the port were moved to Navotas and the area of Dagat Dagatan in Caloocan City just north of Tondo.The Marcos regime, which had implemented martial law in 1972, shared an understanding of urban hierarchy with not only World Bank workers, but also officials at the United Nations and the Asian Development Bank. This shared thinking organised national space by its current and potential contributions to economic development, the national economy and, eventually, global economic networks. In the eyes of these planners, Greater Manila was the dominant economy, and all the other regions, extensions.The extension is never designed to take over the core urban dwellers have no trouble discerning this intentional hierarchyBut the remote resettlement areas did not function as true extensions of the city: people sent to live there did not have access to the local rural economies, were rejected by their new rural neighbours, and fled back to Manila if they were able. The idea that remote areas could be populated with urban dwellers and that the dense metropolis could be drained into neighbouring extensions simply did not work in practice. The true extensions of core urbanism existed in alleyways, in the selfmade stilt houses hovering precariously over esteros (rivulets), and along the banks of waterways.Though World Bank funding shifted towards housing finance at the end of the 1990s, the ideas surrounding core housing provision and self-built extensions have continued to interest architects such as Elemental, whose 2003 project Quinta Monroy in Iquique, Chile provided extendable cores for 93 households. In 2021, all but one household had extended their homes beyond Elementals planned parametersCredit:Cristbal PalmaDuring the Philippines nine years of martial law, as well as after the restoration of democracy in 1986, informality was resilient and not just in Tondo. The methods by which lowincome urban dwellers learnt to make life liveable by extending power lines illegally through settlements, by extending stilt houses over Manila Bay and over the numerous esteros that thread the city continued throughout the 1980s, 90s, and indeed, to this day. Ironically, perhaps, the kinds of housing that planners imagined would most empower residents by encouraging them to add extensions and by encouraging them to use their selfhelp strategies to build amenities, instead became listless spaces where people felt disconnected from the possibilities of the city. For the government, desirable housing extensions were the luxury of an additional bedroom or even a second storey; for residents, desirable extensions were those that made life more liveable in central Manila. Meanwhile, those families unfortunate enough to have been resettled far from the central city in a sites and services project did not see themselves as even a part of an extended Manila. Resettled urban dwellers more often viewed themselves as cut off from urban life, disconnected from former jobs and rejected by both the city and their new rural neighbours, many of whom opposed their arrival.Tellingly, even after the People Power Revolution successfully removed Marcos from the presidency in 1986, slum clearance and evictions continued under the democratic political regimes that followed. Tondo residents expressed shock and dismay as they found themselves subject to the same urban clearing tactics under Corazon Aquino as they had endured for 14 years under Marcos.From 1972 to 1986, more than 70 per cent of all of the World Banks housingrelated loans were for sites and services and squatter upgrading. By 1998, this had amounted to roughly US$14.6 billion spent on 100 sites and services projects in 53 countries. For about 15 years, until it shifted to housing finance programmes, the World Bank was the largest single organisation to encourage these practices at scale.More recently, architect and academic Stephen Cairns designed an expandable house in Batam, Indonesia one of the worlds fastest-growing citiesCredit:FCL Singapore, Carlina TeterisSites and services fell out of favour by the end of the millennium, abandoned by donors and governments alike for being too expensive and serving too few. They had turned out to be overly dependent on building skills in the general population; poorly coordinated with employment sites; or otherwise ineffectively implemented. All of these critiques are fair and responsive to historical experiences. However, no perfect solution has come along to replace some of these midcentury experiments, and other trials with land titling and home lending have produced equally problematic results. Indeed, in 2022, we came full circle: the World Bank Group published a careful study called Reconsidering Sites and Services, looking for techniques worth reviving.One of the most important lessons in looking at evolving ideas about core and extension in housing is a simple one: so long as some urban residents are seen as not belonging in the core of the city, so long as they are peripheral or marginal to the investments made in a separate urban core, informality will persist and grow. Extensions can only be extensions if they are connected to a centre. And so, in the case of forced remote resettlement, it is hard to argue that these projects indeed extended the city in some way. In addition, extensions are, by definition, second to a core. The extension is never designed to take over the core, nor is it meant to be equal to it. Urban dwellers have no trouble discerning these intentional hierarchies. And in the end, whether DIY housing extensions were done because of creativity, desperate need or something in between, they never fully erased dwellers longing for more equitable distribution of core resources.Whether folded into the design of a core unit, or entirely constructed by residents themselves, extensions will persist among urban dwellers whose needs are not met by formal buildings. Artist Marjetica Potrs installations revolve around such negotiations of housing and infrastructure provision above is an installation view from Architektonika 2, a 2012 exhibition at the Hamburger Bahnhof in Berlin, in which Potr examined self-built housing in CaracasCredit: Marjetica Potr / Courtesy the artist and Galerie Nordenhake / Photo: Gerhard KassnerThis is the Keynote essay from the AR February 2025: Extensions. Buy your copy at the ARs online shop, or read more from the issue here2025-02-04Reuben J BrownShare