• 1 The microbrigade is a Cuban concept of state-subsidized self-built housing introduced in 1971. A m (...)

2In October and November 1990, just weeks after the reunification of Germany on October 3rd, six students and their lecturer Horst Schroeder from the University of Architecture and Civil Engineering Weimar (Hochschule für Architektur und Bauwesen, HAB) in the former German Democratic Republic travelled to Havana to work on the project together with staff of the Technical University of Havana (Instituto Superior Politécnico José Antonio Echeverría, ISPJAE) and with the help of a Cuban microbrigade.1 During their six-week stay in Havana, the group from Weimar met numerous obstacles like material scarcity and unexpected material properties. Eventually, only parts of the structure had been built on the day of their departure. However, in the following years several Cuban microbrigades completed the construction of the building, and it still exists today as a fully inhabited apartment building.

• 2 The project is mentioned in the files in Weimar (Germany), Bauhaus-Universitätsarchiv (BUnivA), I/ (...)
• 3 We employ the term “Eastern Europe” in the political context it acquired during the Cold War, foll (...)
• 4 See the example of housing projects built in countries such as Vietnam and Namibia after 1990 as a (...)
• 5 Manfred Engert and Heinz Stephan (eds.), Lexikon RGW, Leipzig: Bibliographisches Institut, 1981, p (...)
• 6 Christina Schwenkel, “The Afterlife of Architectural Aid to Vietnam: A View from the Global South, (...)
• 7 James Mark, Steffi Marung and Artemy Kalinovsky, “Introduction,” in Idem (eds.), Alternative Globa (...)
• 8 Łukasz Stanek, “Gift, Credit, Barter. Architectural Mobilities in Global Socialism,” E-flux, 2020. (...)

3Planned in 1988-89,2 this joint project can be read as a belated material legacy of the international solidarity network that connected the GDR and other countries of socialist Eastern Europe3 with countries across Asia, Africa, and Latin America which were either undergoing decolonization or where a trajectory to socialist development seemed possible.4 The GDR granted “economic” and “scientific-technical cooperation” (wirtschaftliche and wissenschaftlich-technische Zusammenarbeit) to emphasize the cooperative character with the proclaimed aim of “equalizing the level of economic development.”5 Services from the construction sector were also part of this type of cooperation. Anthropologist Christina Schwenkel noted that European socialist modernity often spread through architecture, with cities from Tanzania to Vietnam becoming “laboratories” for these experiments, framed as “assistance,” “solidarity,” and “mutual cooperation.”6 The flow of architecture and knowledge within the socialist political economy—often referred to in the GDR as material or immaterial “export of construction services”—presents a facet of an “alternative globalization”7 and reveals an "ambiguous relationship between gift-giving and commercial exchange," as Łukasz Stanek puts it.8

• 9 Michael Zeuske, Insel der Extreme. Kuba im 20. und 21. Jahrhundert, Berlin: Rotpunktverlag, 2017, (...)
• 10 Antonia Bihlmayer, DDR-Sozialismus in der Karibik? Die ostdeutsche Kuba-Politik zwischen 1959 und (...)

4After the USSR, the GDR was the second most important economic partner for Cuba among the countries that belonged to the Council for Mutual Economic Assistance (COMECON).9 Numerous exchange and training programs linked the two states on an economic, cultural, and diplomatic level. Cuba had great historical significance for the GDR, as in 1963 it was the first country in South and Central America in which the GDR was allowed to open an embassy. At the same time, the Cuban officials were often regarded as difficult partners, as they did not submit to the explicit or implicit German expectations that the island-state behave like a lower-ranking counterpart. They often irritated the somewhat ossified GDR bureaucrats up to the highest state level with their unorthodox concepts of socialism and their self-proclaimed role in the vanguard of Third World internationalism.10 Through an examination of the history of the Cocosolo Experimental House project, we aim to analyze a specific material outcome of the GDR’s international solidarity efforts, which can be viewed as a manifestation of the challenges encountered in cooperation.

• 11 Susanne Ritschel, Kubanische Studierende in der DDR, Hildesheim: Georg Olms Verlag, 2015, p. 46.
• 12 Weimar (Germany), Bauhaus-Universitätsarchiv (BUnivA), I/11/192, Internationale Zusammenarbeit Sch (...)
• 13 N. a., “40 años de la CUJAE,” EcoSur. URL: https://www.ecosur.org/index.php/es/edicion-37-dic2010/ (...)
• 14 BUnivA, I/20/113, Grundsätze der Zusammenarbeit zwischen HAB und ISPJAE Havanna/Kuba, 1978-89.
• 15 Farhan Karim, “Dirt, the Progressive Primitive,” in Daniel A. Barber, Lee Stickells, Daniel J. Rya (...)
• 16 Johan Lagae and Kim De Raedt, “Editorial: Global Experts ‘off radar,’” ABE Journal, no. 4, 2013. D (...)
• 17 This constructed preference for “traditional” materials often still resonates in the present, as d (...)
• 18 E. g. John A. Loomis, Revolution of Forms: Cuba’s Forgotten Art Schools, New York, NY: Princeton A (...)

5The Cocosolo House was a collaborative project of two “Building in the Tropics” chairs at the universities of Havana and Weimar. The Scientific Department of Building in the Tropics and Abroad (Wissenschaftsbereich Tropen- und Auslandsbau), founded at the HAB Weimar in 1985, was to conduct the construction itself. The department had served as the central link between Weimar and Cuba ever since the HAB and the ISPJAE in Havana established a “scientific-technical cooperation” agreement in the mid-1970s,11 which included joint research agendas.12 The establishment of the Center for Tropical Architecture and Building Studies (Centro de Estudios de Construcción y Arquitectura Tropical, CECAT) marked a step towards a more research-focused collaborative endeavor at the ISPJAE. Led by Rubén Bancroft, drawing on his experiences from his doctoral studies in Weimar, CECAT researched climatically adapted building techniques and energy-efficient materials, with practical implementation as a primary goal.13 The inter-university agreement of 1989-90 outlined the “preparation and construction of a joint experimental building using local earth materials” in Havana.14 Subsequently, the project that explicitly incorporated loam as a primary material was added to the collaborative agenda, with CECAT handling the overall design and construction site management. By focusing on the material constraints—limitations on the type, quality, and availability of construction materials—, and their effects on collaboration and the construction process, the case of Cocosolo contributes to the literature on the material impact of self-help practices and building with earth in the global developmentalist discourse in the 1970s and 80s.15 In those years, “global experts”16 from the Global North often promoted earth-building to address housing shortages in the Global South.17 Paying close attention to this small-scale architecture and its materiality can thus contribute to a more nuanced architectural history than the sole emphasis on canonical buildings of Cuban modernist architecture, like the Escuelas Nacionales de Arte (National Art Schools), would allow.18

• 19 Hochschule für Architektur und Bauwesen Weimar Wissenschaftsbereich (eds.), Bauingenieurpraktikum (...)
• 20 Terminological confusion commonly arises in general and technical usage of the terms. To clarify, (...)
• 21 We use the term “tropics” as a source term. At the same time we understand “tropics” not as a cert (...)
• 22 Hochschule für Architektur und Bauwesen Weimar Wissenschaftsbereich (eds.), Bauingenieurpraktikum, (...)
• 23 Interviews were conducted with the head of the project team from Weimar, Horst Schroeder, in Augus (...)
• 24 For further reflections on interviews and oral history in architectural historiography, see Janina (...)

6This article is structured around the project partners’ divergent expectations and their ramifications. First, we analyze the Weimar group’s view of the project as a prototype for self-construction technology in Cuba19 and a chance to apply their loam20 construction expertise in a “tropical” setting.21 Next, we explore the Havana partners’ view of Cocosolo as a prototype for rarely tested soil cement construction. Finally, we show how these conflicting expectations caused tensions on the construction site. We have researched the archives of today’s Bauhaus University, formerly the HAB in Weimar, as well as private archives of contemporary witnesses from Germany and gray literature.22 Since no information on the house could be located in official archives in Cuba, the private archive of Alfonso Alfonso González, the former supervisor of the Cocosolo project and CECAT member, was essential. It is important to address Alfonso’s multifaceted role. In addition to being a co-author of this paper, he is a scientist with extensive publications on the practical experiments discussed below, and a contemporary witness. His recollections, alongside with other interviews with the engineers and students involved,23 contribute to an oral history collection that corroborates written archival records, preserving and transmitting informal dimensions often absent from bureaucratic documents.24 At the same time, these memories are necessarily retrospective and subjective and must be critically compared with other sources. In the ping-pong way this article developed, we were comparing, juxtaposing, and challenging our conclusions. In this way, we discovered knowledge gaps and biases in our research, thus reflecting our positionality vis-à-vis our object of research and the conditionality of our observer position(s).

• 25 Toni Miller, Lehmbaufibel, Darstellung der reinen Lehmbauweisen, Weimar: Forschungsgemeinschaften (...)
• 26 Horst Schroeder, Lehmbau, Wiesbaden: Springer Vieweg, 2019, p. 19-22.
• 27 Overview in Richard Rath, Der Lehmbau in der SBZ/DDR, Diploma thesis, Technische Unviversität Berl (...)
• 28 Dong-Sam Sin, Die Planung des Wiederaufbaus der Städte Hamhŭng und Hungnam in Nordkorea durch die (...)
• 29 Berlin (Germany), Bundesarchiv, Muster- und Experimentalprojekt, DH 2/10119, DH 2/10120, DH 2/1012 (...)
• 30 Michael Persike, “Grundsätze eines sozialistischen Technologietransferkonzeptes,” Wissenschaftlich (...)
• 31 Richard Rath “Der Lehmbau in der Sowjetischen Besatzungszone und der ehemaligen DDR 1945−1989,“ Be (...)
• 32 Michael Persike, “Grundsätze,” op. cit. (note 30), p. 109; See Institut für Aus-und Weiterbildung (...)

8The history of Weimar University’s involvement with loam goes back to the post-war period when construction materials like cement were scarce.25 However, the importance of loam construction declined steadily from 1960 onwards26 and it was not until the 1980s that research re-appeared in scientific institutions. Working groups at the universities of Stralsund, Dresden, and Weimar, and at the East Berlin Bauakademie, the central research institute for architecture in the GDR, studied loam buildings and built experimental dwellings.27 Some earlier projects operated under the umbrella of “export orientation” to apply loam building knowledge abroad, for example in North Korea and Kazakhstan in the 1960s.28 But only in the 1980s were export possibilities researched systematically, when the Muster- und Experimentalprojekt department of the Bauakademie examined the potential for “advancing loam building methods for arid climate zones.”29 Members of the Bauakademie also published articles on construction with loam abroad in the HAB journal from the standpoint of “socialist technology transfer.”30 These endeavors, which varied in both scope and purpose (for use as an exportable technology or simply as a reason to study loam during times of material shortages), ultimately created a specific space for testing31 and dissemination of knowledge.32

• 33 Frank Fischer, Hans-Ulrich Mönnig, Horst Schroeder and Bernhard Wagner, “Ein Jugendklub aus Lehm,” (...)
• 34 Ibid., p. 165.
• 35 Hans-Ulrich Mönnig, “Erdstoff als Baustoff,” Wissenschaftliche Zeitschrift der HAB Weimar, vol. 35 (...)
• 36 Frank Fischer, P. K. Kiefer, Hans-Ulrich Mönnig, Frank Mücke, Horst Schroeder, Analyse zur Verwend (...)
• 37 Michael Persike, Wolfgang Dehmel, Andreas Albert and Roland Golembiewski, “Weiterentwickelte Lehms (...)
• 38 Farhan Karim, “Dirt,“ op. cit. (note 15), p. 265. See John E. Cox, “Objectives of the UN Internati (...)
• 39 Hubert Guillaud, Dominio del material tierra y desarrollo de sus potencialidades arquitectónicas, (...)
• 40 Hugo Houben, Hubert Guillaud /CRATerre, Traité de construction en terre, Marseille: Editions Paran (...)

9A site of domestic experimentation with loam directly within the HAB context was the “Experimental Building Site Herbsleben,” a building ensemble in a hybrid construction of rammed loam and prefabricated reinforced concrete elements. It was visited by the students in preparation of the Cocosolo project.33 Contemporary reports on this project outlined its objective to test loam building techniques as sustainable alternatives to energy-intensive construction materials,34 implying the suitability of this technique for diverse “developing countries.” “Lehm” (loam), often referred to as “Erde” (earth), was perceived as a universal solution, given that “suitable earth materials for construction [are] available in almost all regions of the world.”35 Similar lines of argumentation regarding the affordability, accessibility, sustainability, and adaptability of earth as a building material for developing countries can be found in other Weimar studies examining (sub-)tropical soils as potential building materials.36 Additionally, these experimental buildings were assessed for their suitability as self-help construction projects, bridging the connection between “simple” building materials and “simple” technology,37 a trope that was ultimately applied to the Cocosolo project. These considerations followed the international trend. Farhan Karim underscores the decisive role of international organizations such as the United Nations Human Settlements Program (UN-HABITAT), sponsoring conferences and initiatives like the “International Year of Shelter for the Homeless” in 1987.38 Additionally, advocacy groups like CRATerre, which were also active in Cuba,39 played a significant role in advancing the idea that local building materials and techniques could alleviate housing shortages in “developing countries.”40

• 41 E. g. see those referenced in note 32.
• 42 E. g.: Georg Lippsmeier, Tropenbau = Building in the Tropics, München: Callwey, 1969; René Gardi, (...)
• 43 As Marc Crinson notes, “in the naming of something as ‘vernacular,’ a symmetrical structure of opp (...)
• 44 HAB, Bauingenieurpraktikum, op. cit. (note 19), p. 50.

10These approaches often combined ideas of “earth architecture” with “traditional architecture.” Close examination of East German literature and manuals concerning construction in “hot climates”41 reveals that they relied largely on literature from (Western) countries in the Global North, and rarely from the Global South.42 These documents frequently juxtapose “traditional” and “modern” technologies, wherein the latter are typically linked with concrete and industrialized materials, while the former encompass raw and untreated materials, echoing a common perspective within the study of vernacular architecture.43 The report on Cocosolo reflects this approach and underscores the Weimar team’s emphasis on the importance of “understanding traditional building methods and materials [...] for professional use.”44 Despite this assertion, however, the team possessed a limited understanding of the historical context of earth architecture in Cuba and the specific nature of soils in the Havana area, as will be shown below. The application attempted by the Weimar group pertained to their expertise in building with loam, resulting in a kind of self-imposed epistemological constraint.

• 45 The information regarding the introduction of this construction method in a neighborhood like Coco (...)
• 46 For further context of Havana’s urban development, see Timothy Hyde, Constitutional Modernism, Arc (...)
• 47 Juan de las Cuevas and Gina Rey, Las construcciones cuentan su historia, Havana: Ediciones Boloña, (...)
• 48 CEMBUREAU, “Industria cementera europea y la contaminación ambiental,” Construcción y tecnología, (...)
• 49 The “periodo especial,” starting in September 1990, was characterized by shortages of materials, f (...)
• 50 Omar E. Pérez, “La construcción de vivienda en Cuba, antecedentes y situación actual,” La Joven Cu (...)
• 51 Dania González, “¿Viviendas,” op. cit. (note 48), p. 25.
• 52 Alfonso Alfonso González, “Materiales de construcción con residuos industriales de vertederos ecol (...)
• 53 These attempts paralleled debates and experiments in other South American countries like Bolivia, (...)
• 54 IT-07-91: CODASE. Ladrillos macizos de suelo cemento, Havana, 1991.

11The goals of the ISPJAE university staff for the Cocosolo experiment were distinct, as they primarily aimed at applying soil cement with the intention of eventually expanding upon the gathered insights. They selected the building site in the Marianao district, suggesting that conditions could be enhanced through minor interventions and easily learnable and adaptable building techniques.45 The district is known for its high proportion of informal construction, colloquially referred to as quita y pon (“remove and put”) in reference to the adaptive nature of construction practices involving reuse and improvisation.46 Experimentation with “alternative” building materials in Cuba originated from two primary sources: environmental and economic concerns. Constructing with concrete had been the prevailing practice in Cuba since the introduction of Portland cement production in 1895.47 However, by the 1980s, its use was questioned due to its high energy consumption and environmental impact.48 Adding to this, the nation was sliding into a profound economic crisis, triggered by the decline of soviet assistance following 1989, later named “special period in times of peace” (“periodo especial en tiempo de paz”).49 The shortage of oil imports, important for the production of building materials, led to the almost total halt in the construction of houses.50 Against this background, attempts were made to develop “alternative technologies,” which were essentially “no-alternative” solutions—more necessity than choice.51 Fired ceramic bricks were abandoned due to their high energy consumption; further efforts included exploring biomass for firing, using stone blocks from natural limestone, and employing industrial waste and residues from sugar production and the paper industry.52 However, the predominant choice was soil cement, which drastically reduced the amount of cement needed compared to concrete.53 On the national level, the Ministry of Sugar (MINAZ) undertook the construction of a cluster of houses made of soil cement in San Nicolás de Bari and the ISPJAE supported the investigations in the Havana district La Güinera. Experiments like these led to standardization attempts, such as the regulatory document for soil cement constructions, the IT-07-91: CODASE,54 published by the National Soil Cement Commission (Comisión Nacional del Suelo-Cemento). However, the reports reproduced biases, as they used standards meant for materials like reinforced concrete or conventional cement constructions to assess the compressive strength or drying time of soil cement bricks. Also, e. g. for the houses in San Nicolás de Bari, too much cement was used and the soil aggregate was transported over too long distances, which drove up production costs.

• 55 Alfonso Alfonso González and Dania González, “Las alternativas bioclimáticas del ecodiseño en Cuba (...)
• 56 Fernando Rodríguez, “La tierra ¿Un material olvidado?,” Arquitectura y Urbanismo, vol. 10, no. 3, (...)
• 57 N. a., MicroConcrete roofing tiles, Ecosur. URL: http://www.english.ecosur.org/index.php/products/ (...)
• 58 Enrique Amat and Alfonso Alfonso González, “Impermeabilidad y durabilidad en los muros de suelo ce (...)
• 59 Gabriela Peterssen et al., Manual de construcción con elementos de suelo cemento conformados en pr (...)

12One of the most important knowledge hubs regarding energy-saving materials was the CECAT at the ISPJAE.55 This included research in soil cement techniques, as well as investigations in—more broadly—earth construction techniques, aiming to re-discover this “forgotten building technique” in Cuba.56 What is more, CECAT also developed and exported a master’s degree program to Peru and Nicaragua as well as precise technological systems, like dry-assembled hollow block panels to Peru or cement-saving roof tile systems (TEVI),57 as proposed for the roofing of the Cocosolo house, too. Parallel to this, in order to research compressive strength and resistance to humidity,58 the CECAT initiated a study on soil cement which culminated in a manual for professional training and self-help housing59 and involved the planning and construction of a demonstrative prototype: the “Casa Experimental Cocosolo.”

• 60 Hochschule für Architektur und Bauwesen Weimar Wissenschaftsbereich (eds.), Bauingenieurpraktikum, (...)

14Leveraging their broad range of experiences and backgrounds in earth construction, the groups endeavored to apply their knowledge at the construction site, which inevitably led to confrontations. A contradiction emerged in their differing perceptions of what constituted “traditional” building materials. In their report, the Weimar group frequently referred to the “traditional” earth-building techniques they were seeking to revive in Cuba,60 while remaining ambiguous about the specific reference.

• 61 As defined in Gernot Minke's standard work on the subject, translated into Spanish in 1994, see Ge (...)

15Studying the historical presence and development of earth architecture in Cuba from the pre-colonial era to the 20th century presents challenges. One significant issue is the translation dilemma surrounding the term “barro.” In German, “barro” translates to “Lehm,” which refers to a mixture of clay, sand, and gravel.61 However, the Spanish term "barro" encompasses broader meanings such as “earth,” “dirt,” or “mud,” complicating its interpretation of whether it specifically refers to “loam” or more generally to “building with earth.” Thus, we must consider earth construction in Cuba more broadly.

• 62 Juan de las Cuevas, 500 años de construcciones en Cuba, Havana; Madrid: Chavín, 2001, p. 3.
• 63 María Del Rosario, Miguel Ángel Rodríguez, Belkis Saroza, Idamnis Monteagudo, Yami Castro, Fernand (...)
• 64 Juan de las Cuevas, 500 años, op. cit. (note 62), p. 3-20; Joaquín Weiss, La arquitectura colonial (...)
• 65 It was not until the mid-1980s that the rural bohío was rediscovered and identified as the vernacu (...)
• 66 Juan de las Cuevas, 500 años, op. cit. (note 62), p. 9-10.
• 67 This mindset persisted into the early 2000s during the partial restoration of the Escuela Nacional (...)

16The indigenous population employed the red earth of the island for the floors of their houses, known as bohíos, while constructing walls and roofs from organic material like palm tree parts (yagua, guano, penca, tabla). Spanish colonizers continued this practice, later reinforcing walls with woven wedges and branches and a mixture of earth and grass.62 Earth construction peaked in Cuba between the 17th and 19th centuries, albeit with a strong regional emphasis in the central and eastern provinces.63 Nevertheless, building authorities were hostile to the bohío, and ousted it from urban centers, especially Havana,64 and the dwelling type was later outlawed by the Cuban Revolution as well.65 Additionally, regional disparities in the use of fired ceramic bricks further complicate the landscape, with Havana lacking suitable clay deposits. Therefore, fired clay bricks and terracotta were imported from Spain,66 exemplifying a (colonial) disregard for local building material production.67

• 68 Xavier Tafunell, “On the Origins of ISI, The Latin American Cement Industry, 1900-30,” Journal of (...)
• 69 Gabriela Peterssen, Alfonso Alfonso González and O. Echenique, Estudio de factibilidad de bloques (...)
• 70 This ambiguity recalls the widespread perception that cement (and consequently concrete) is an art (...)

17Conversely, concrete construction had been the predominant building technique in Cuba in the 20th century.68 The fixation on cement as the primary building material even led some building officials to conclude that cement was actually the more “traditional” building material in Cuba. This is evident in the soil cement projects of La Güinera, which were accompanied by a document reporting that “there was still a sufficient supply of traditional materials”69—with “traditional” referring to cement,70 so there was no need to rely on earth.

• 71 Interview with Horst Schroeder, 16.08.2021.
• 72 INSMET, Atlas Nacional de Cuba, 2023.
• 73 As noted by Karl Petzold, Bauen in warmen Klimaten. Bauklimatische Grundlagen, Leipzig: Inst. für (...)

18Positioned between these perspectives, the Weimar group clearly advocated for earth architecture. They briefly mentioned the historical bohíos, but the rationale behind their recommendation to use specifically loam remains ambiguous. It is uncertain whether this suggestion stemmed from a research error71 or a perception of loam as a fitting building material for various “tropical” regions. Besides the unavailability of suitable earthworks material in Havana, the limited presence of earth architecture is attributed to the unsuitability of solid earth construction techniques for humid climates, which are prone to frequent flooding and hurricanes (fig. 6).72 The Weimar group should have suspected this might be the case, considering their prior study of loam dwellings were primarily conducted in arid regions such as Yemen. Furthermore, the manuals and study literature of the GDR explicitly discourage the use of loam in humid areas.73

• 74 Jennifer Ferng, Jiat-Hwee Chang, Erik L’Heureux and Daniel J. Ryan, “Climatic Design and Its Other (...)
• 75 Eric Hobsbawm and Terence Ranger, The Invention of Tradition, Cambridge: Cambridge University Pres (...)

19The fixation of architects and ethnographers on the “traditional vernacular house” in tropical settings is not exclusive to the Weimar group’s endeavor; similar tendencies are discernible in various regions, where the purported traditional content often appears peripheral or artificially constructed.74 While the Weimar group did not directly invent any traditions,75 they did engage in imaginative reconstructions, mirroring comparable lines of thought and projecting an imaginary tradition on the Cuban context. Beyond that, the argumentation may have practical underpinnings with the emphasis on loam in the report serving to extrapolate from domestic experiences and thereby validate the project and its funding.

• 76 Hochschule für Architektur und Bauwesen Weimar Wissenschaftsbereich (eds.), Bauingenieurpraktikum, (...)

20Ultimately, the domestic loam-building experiments were applicable only to a limited extent. The properties of the soil, found eventually, differed from the East German architects’ expectations. Instead of loam, they found a fine-grained soil (Capdevilla), which needed a binder. So just as the CECAT members had planned, cement had to be added.76 However, soil cement behaves differently from an all-earth building material, with serious consequences for the construction process. Soil cement bricks, unlike those made of loam or mud, must cure under prolonged exposure to continuous saturated humidity in the shade. This process takes a much longer time, which the HAB group had not factored in. Finally, the volume of soil cement changes during the curing process, and this was already before a challenge for the Cuban researchers and practitioners advocating its use.

• 77 Benedikt Brester, “Housing,” op. cit. (note 1), p. 76-77. Of 680,000 dwellings built between 1959 (...)
• 78 Michael Persike, Wolfgang Dehmel, Andreas Albert and Roland Golembiewski, “Weiterentwickelte Lehms (...)
• 79 The narrative of the “disorganized” Cubans pervades the GDR’s archival sources on cooperation with (...)
• 80 Hochschule für Architektur und Bauwesen Weimar Wissenschaftsbereich (eds.), Bauingenieurpraktikum, (...)
• 81 And even reinforced by architects who were advocates of these materials, like the very title of Ha (...)
• 82 Richard Rath: Der Lehmbau, op. cit. (note 27), p. 22.
• 83 Jean Dethier, Lehmarchitektur, op. cit. (note 42), p. 17.

21Cocosolo built substantially on the idea of self-construction, offering a blueprint for construction without sophisticated technology. Given the prevalence of self-build practices in Cuba,77 it is unsurprising that the microbrigade labor model was implemented in the Cocosolo project. But the groups faced serious constraints such as supply bottlenecks and the scarcity of construction materials. Contrary to what GDR experts demanded in their studies,78 the earth building material could not be sourced directly from the excavation pit. Instead, it was located up to six kilometers away. This was not appropriate in Cuba with the economic crisis approaching, when trucking was unreliable. Additionally, the organizational methods employed at the Cocosolo construction site often disappointed the engineers from Weimar, which led to tensions.79 It was not until the last day before departure that they erected a section of masonry (fig. 7), which, as stated in the Weimar report, “seemed particularly important to us in order to counteract the skepticism still widespread in Cuba about this construction method.”80 This skepticism has been a constant obstacle for proponents of earthen architecture, from its reintroduction in 18th-century Western Europe to its advocacy in the developmentalist context of the 1980s. It was often seen as the unhygienic material of shortage, of the poor and backward, far inferior to construction methods using natural stone or reinforced concrete.81 As Richard Rath describes it, loam “never lost the smell of ‘replacement construction.’ As soon as it could be replaced itself, it was replaced.”82 Simultaneously, earth construction has been regarded as a method of autonomy,83 enabling unskilled construction workers to build their own houses. This aspect likely influenced the decision of the Weimar team to integrate self-build technology with earth construction for Cuba.

• 84 Interview Horst Schroeder, 16.08.2021.
• 85 Aggregate, Architecture, op. cit., (note 15), p. 3.
• 86 Interview Horst Schroeder, 16.08.2021.

22Horst Schroeder later reflected: “Our colleagues of the microbrigade have learned how to lay bricks, handle a trowel, determine mortar stiffness, interlock a corner, and create a masonry bond.”84 In a way, the “tools” the Weimar team could pass on were skills that they imparted to the microbrigade members. Although Schroeder’s statement suggests they acted as knowledge mediators, it is clear from the reports and memories of the contemporary witnesses (like Alfonso) that the foreign partners did not act as “epistemic authorities,” as was often the case in development aid contexts.85 Instead, they viewed themselves as learners, engaging in improvisation and collaborative problem-solving, such as procuring materials and conducting laboratory tests alongside CECAT.86 Notably, the CECAT staff leveraged their knowledge of soil cement technology, a domain in which the Weimar team completely lacked experience.

• 87 Interview Martina Schulle, 14.02.2024.
• 88 Hochschule für Architektur und Bauwesen Weimar Wissenschaftsbereich (eds.), Bauingenieurpraktikum, (...)
• 89 Farhan Karim, “Dirt,” op. cit. (note 15), p. 241; see also Farhan Karim, “Reinventing earth archit (...)
• 90 Frank Fischer, Hans-Ulrich Mönnig, Horst Schroeder and Bernhard Wagner, “Ein Jugendklub aus Lehm,” (...)
• 91 For the history of “design-build” chairs in (Western) Germany see Vera Simone Bader, “In der Ferne (...)
• 92 Stefan Wolle, “Das System der Reisekader als Instrument der DDR-Wissenschaftspolitik,” in Deutsche (...)
• 93 Highlighting the shortcomings and challenges posed by issues of privilege in the application of su (...)
• 94 This was also criticized by Horst Schroeder, who complained about the lack of distance standards a (...)
• 95 Hochschule für Architektur und Bauwesen Weimar Wissenschaftsbereich (eds.), Bauingenieurpraktikum, (...)

23Despite the existing tensions, the collaborative physical labor on the Cocosolo construction site fostered closer relationships among the participants, as recounted by those involved.87 Using the hand lever press model CINVA-RAM, the group eventually created 700 soil cement bricks in five days, through a labor-intensive process of repeated sieving, mixing, pressing, and stacking (fig. 8).88 Farhan Karim observed that manual construction methods were discussed by international experts as a way to “engage users in a hands-on, sensory and immersive participatory experience that is essential to creating a sense of community.”89 In the Cocosolo case, however, the joint manual work was not introduced by outside experts. Both groups already had experience with hand lever presses: the CINVA RAM was in the possession of the CECAT, and the Weimar team had built a DIY-version of a TEK Block press at the HAB Weimar, similar to the CINVA RAM model.90 The underlying spirit of many design-build projects is nevertheless evident here.91 Especially for the Weimar students and their instructor, this trip was a unique and first-time opportunity, as only a limited number of people were able to travel prior to the opening of the GDR borders.92 The Weimar group’s search for an immersive experience and meaningful work led to hands-on pragmatism characterized by physical labor, improvisation, and creativity in finding solutions.93 Ultimately the project was conducted within a relatively short timeframe without the need to adhere to (German) building norms and standards.94 The privilege of being (practically overnight) from a part of the Western (capitalist) world, with access to funding and the freedom to travel was also a factor here.95

• 96 Hochschule für Architektur und Bauwesen Weimar Wissenschaftsbereich (eds.), Bauingenieurpraktikum, (...)

24In the end, the Weimar and CECAT groups left the project unfinished. But contrary to the concerns expressed in the project report, recommending a second trip to Cuba,96 Cocosolo was completed by various microbrigades by 1993. Although smaller than its originally envisioned dimensions, it was nevertheless accomplished through the local practice of self-construction.

• 97 As conceptualized by Michael Persike, “Grundsätze eines sozialistischen Technologietransferkonzept (...)

26The involvement of the Weimar University and their focus on loam stemmed from GDR-era knowledge and practices. On-site, it became clear that the Weimar assumptions faced material constraints, such as the unavailability of suitable earthen materials and supply bottlenecks, exacerbated by the economic conditions. These constraints also affected the building process in terms of time, which the Weimar group did not account for in their planning. On the other hand, the perspective of the Cuban team highlights the importance of considering local agendas when planning projects in different contexts. Emphasizing a “socialist technology transfer”97 from East Germany to Cuba would undermine the crucial role of the CECAT staff: Although the experiment perhaps failed to meet the direct expectations of the GDR group, the Cuban stakeholders harbored their own expectations for the project, navigating the initially divergent agendas and expectations of the Weimar group while pursuing their own objectives. Additionally, both parties ultimately gleaned practical insights into soil cement construction, particularly valuable for the Weimar group who lacked expertise in this area.

• 98 Except for an essay recently published by the co-author of this article. See Alfonso Alfonso Gonzá (...)
• 99 Kosta Mathéy, Kann Selbsthilfe-Wohnungsbau sozial sein?, Ph.D. dissertation, Gesamthochschule Kass (...)
• 100 Rubén Bancroft, “Alternative Building Materials and Technologies for Housing Construction in Cuba, (...)

28Despite challenges and interruptions during construction and the subsequent abandonment by both the Weimar group and CECAT, local microbrigades completed the project during the severe crisis of the special period. This completion, although not widely publicized,98 showcased the durability of the building, evidenced by its resilience against natural disasters like the “Storm of the Century” in 1993, cyclone Irene in 1997, and hurricanes Charley (2004) and Dennis (2005), which caused widespread destruction in the city. Though the construction technique of the Experimental House Cocosolo remained unique in its neighborhood, and building with stabilized earthen bricks could not be established on a larger scale within the microbrigade movement,99 Cocosolo formed a starting point for further soil cement research and networks in Cuba. These efforts continued into the late 1990s under the low-cost housing framework (bajo consumo).100