Politecnico di Milano , Milan, Italy DESIGN OF ULTRA LIGHTWEIGHT BUILDING SYSTEM Alessandra Zanelli A.Y. 202 5 - 202 6 Copyright © 20 2 6 by Leandro Limoncelli under permission of License Creative Commons CC BY - NC - ND 4.0 The nomadic lesson for ultra - l ightweight architecture Leandro LIMONCELLI * * Politecnico di Milano , M .Sc. Architettura e Disegno Urbano Milan, Italy leandro.limoncelli@mail.polimi.it Abstract This paper explores the evolution and contemporary relevance of ultra - lightweight building systems, tracing their theoretical lineage from the Enlightenment to modern humanitarian applications. By examining Marc - Antoine Laugier’s "primitive hut" and Gottfr ied Semper’s theories on textile tectonics, the research establishes a historical foundation for the "lightweight genealogy" of architecture. The study further analy s es the structural logic of Central Asian nomadic dwellings, specifically the Kazakh yurt and Mongolian ger , to identify how traditional assembly methods can inform modern design. Through the evaluation of contemporary case studie s – such as the Jero Yurt and Abeer Seikaly’s "Weaving a Home" – and the presentation of a student - led deployable pavilion project, this document demonstrates how vernacular knowledge and ultra - lightweight approaches can be synthesi s ed to create efficient, portable, and sustainable sheltering solutions for displaced populations in the 21st century. Keywords : Classical architecture, Nomadic architecture, Yurt, Emergency shelter, Lightweight architecture D ULBS 202 6 ______________________________________________________________________________________ 2 1 A “lightweight genealogy” of architecture 1 .1 Marc - Antoine Laugier ; the myth of the petite cabane rustique «It is the same in architecture as in all other arts: its principles are founded on simple nature, and nature's process clearly indicates its rules. Let us look at man in his primitive state without any aid or guidance other than his natural instincts. He is in need of a place to rest. On the banks of a quietly flowing brook he notices a stretch of grass; its fresh greenness is pleasing to his eyes, its tender down invites him; he is drawn there and, stretched out at leisure on this sparkling carpet, he thi nks of nothing else but enjoying the gift of nature; he lacks nothing, he does not wish for anything. But soon the scorching heat of the sun forces him to look for shelter. A nearby forest draws him to its cooling shade; he runs to find a refuge in its dep th, and there he is content. But suddenly mists are rising, swirling round and growing denser, until thick clouds cover the skies; soon, torrential rain pours down on this delightful forest. The savage, in his leafy shelter, does not know how to protect hi mself from the uncomfortable damp that penetrates everywhere; he creeps into a nearby cave and, finding it dry, he praises himself for his discovery. But soon the darkness and foul air surrounding him make his stay unbearable again. He leaves and is resolv ed to make good by his ingenuity the careless neglect of nature. He wants to make himself a dwelling that protects but does not bury him. Some fallen branches in the forest are the right material for his purpose; he chooses four of the strongest, raises th em upright and arranges them in a square; across their top he lays four other branches; on these he hoists from two sides yet another row of branches which, inclining towards each other, meet at their highest point. He then covers this kind of roof with le aves so closely packed that neither sun nor rain can penetrate. Thus, man is housed. Admittedly, the cold and heat will make him feel uncomfortable in this house which is open on all sides but soon he will fill in the space between two posts and feel secur e.» (Laugier 1977, pp. 11 - 12). With this parable, French architectural critic and historian Marc - Antoine Laugier (1713 - 1769) begins the first chapter of his seminal treatise Essai sur l’architecture , published by Duchesne in 1753 in Paris. In what is considered among the founding works of modern architectural analysis, Laugier describes this little rustic hut ( petite cabane rustique ) as the model on which all masterpieces of architecture are based upon. Drawing a parallel to Greek architecture, he compares the upright pieces of wood to c olumns, the pieces placed perpendicularly on top to an entablature and the inclined branches to the pediment. The missing components that we recogni s e in Classical architecture, such as vaults, arches, or even doors, are not crucial to Laugier's thesis, as only the column, entablature and pediment form the essential part of architectural orders. His work then goes on to state the different variations o f these elements that, consequently, characterise the orders; but the origins of this treatise lay in traditional, wooden shelters. D ULBS 202 6 ______________________________________________________________________________________ 3 Figure 1 : Illustration by Charles Dominique Joseph Eisen for th e first edition of Essai sur l’architecture 1 .2 Gottfried Semper; the importance of textile techniques on building history More than a century later, German architect Gottfried Semper (1803 - 1879) published Der Stil in den technischen und tektonischen Künsten; oder, Praktische Aesthetik (1860 - 63), an elaborate theoretical analysis on the Arts – pertaining mainly, but not only, to architecture – expanding on his previously published research Die vier Elemente der Baukunst (1851). This work sets to retrace the origins of architecture but draws to a very different conclusion than his French predecessor Instead of deriving architecture from the proto - Greek model exemplified by the rustic hut, Semper argued that the first architectural act was the weaving of a dressing to form an enclosure ( Einkleidung ). «The concepts of covering, protecting, and enclosing are indissolubly connected with those natural and synthetic covers and dressings that have become the sensible sign for those concepts. As such they form perhaps the most important element in the symboli sm of architecture.» (Semper 2004, p. 123). The four elements he enumerated in his 1851 book – hearth, mound, roof and walls – were found in traditional architectural production all over the world, namely Mesopotamia, Assyria - Chaldea, Media and Persia, China, India, and Egypt. That same year he atte nded the Great Exhibition in London, held in the purpose - built Crystal Palace, and was pleasantly captivated by Persian, Turkish and African textiles and carpets. The sight of a traditional Trinidadian bamboo hut , with woven vertical dividers, was taken as further confirmation of his theories. Strongly influenced by these discoveries and his own archaeological interest, Der Stil follows upon the assertions of Die vier Elemente der Baukunst by associating the titular four elements with technical motives that precede the development of monumental architecture, such as ceramics, carpentry, masonry (or mounding) , and weaving – the latter of which was the one devoted to the walling, the “spatial motive” of delimitation between inside and outside. This study on or igins sits at the core of following architectural research on the onset of the Modern Movement, surpassing – among others – the postulation of a quasi - biblical chronology in Quatremère de Quincy ’s Dictionnaire d'architecture (published in volumes from 1788 to 1825). D ULBS 202 6 ______________________________________________________________________________________ 4 Figure 2 : Illustration of the Caribbean hut from Trinidad seen by Semper at the Great Exhibition of 1851. 1 .3 Nikolaus Pevsner ; the influence of the Arts and Crafts on Modernism Nikolaus Pevsner’s 1936 book Pioneers of the Modern Movement from William Morris to Walter Gropius identifies Philip Webb’s Red House of 1859 as one of the fundamental antecedents of modern architecture. For Pevsner, the building represented a decisive break from the eclectic historicism that dominated n ineteenth - century architecture and embodied principles that would later find fuller expression in the mature phases of Modernism. The Red House was built for – and in close collaboration with – the Pre Raphaelite artist, writer, and textile designer William Morris. He contributed wall paintings, stained glass, textiles, and furnishings specifically for the building, owing to a unified aesthetic vision. The tapestry decorations and ornamental schemes that adorned the interiors were conceived in direct relation to the architectural character of the house. 2 Learning from nomadic experience Having analysed the unexpected textile, woven and otherwise lightweight origins of monumental classical architecture and of the modern movement, a question of succession arises. As this architectural language makes its way back into the discussion of contemporary built environment, with regard to the construction of temporary sheltering solutions, architects would benefit from reviewing past historical experiences in the field. It would be appropriate to think of this as a particular derivation of the post - modernist concept of “critical regionalism” , developed by architects Alexander Tzonis and Liane Lefaivre and, subsequently, by critic Kenneth Frampton ; thus, assuming a critical arrière - garde position that takes the most characteristic elements of local identity and assemblies them through the use of contemporary, universal technique (Frampton 1983, pp. 16 - 30) D ULBS 202 6 ______________________________________________________________________________________ 5 2 .1 The Central Asian yurt and ger A temporary shelter will not be easily found in the history of the largely sedentary populations of Europe. Instead, they have been used for centuries by the inhabitants of the steppes of Central Asia, in contemporary Kazakhstan, Kyrgyzstan and Turkmenistan. The largely nomadic tradition of these populations lasted up until the early Twentieth century, when they all underwent a process of sedentism forced by the Soviet Union. T he communist government’s desire to collectivi s e agricultural lands and centrali s e labo u r led most of the herders to abandon their pastoral life to find more remunerative jobs in the towns , leaving behind their nomadic building s ( Zhdanko 1966, pp. 600 - 620) These structures, known as yurt ( in the Turkic language ) or ger ( in the Mongol language ) are made of a bamboo frame and a felt covering – obtained from the wool of the same sheep that the population were herding This tradition has been documented since the 6 th c entury BC among the Saka and Altai people, nomadic civilisations that inhabited the areas of modern - day Kazakhstan, Uzbekistan, Turkmenistan, Kyrgyzstan and Mongolia. Figure 3 : Kyrgyz yurt photographed in Kizilsu Kyrgyz Autonomous Prefecture, Xinjiang, China by Wikimedia Commons contributor katorisi in 2001 2 1.1 The Kazakh yurt In the Kazakh tradition, the wall is a lattice of wicker bamboo rods bound together with ropes ; this collapsable structure is named kerege The felt insulation applied inside the walls is named tuyrlyk and allows for high thermal mass and breathability On top of the kerege lay the uyk , the inclined roof poles over which the felt covering named uzik is nested to protect from precipitations. Everything is connected through the shanyrak , a compression ring that serves also as a skylight and a ventilation port. This can be closed by a felt cover named tundik , regulated using ropes. The structure is further ensured by circumferential rope belts ( beldeu ) and lariats ( shylbyr ). Neighbouring countries such as Kyrgyzstan have similar enough structure with minimal changes owing to different envir onmental characteristics ( Malibekuly , Semenyuk , Dyisebayev & Kuc 2020, pp. 225 - 230). D ULBS 202 6 ______________________________________________________________________________________ 6 2 1. 2 The Mongol ian ger In the Mongolian Plateau, these huts were built to be shorter, to better resist the intense winds that the nomads met due to the vast openness of the plain (rather than the mountainous, sheltered areas of Kazakhstan). The wall sections ( khana ) are made by crossing willow branches of similar dimension at equal distance, creating a lattice. Each wall section is then connected with cowhide or camel leather strips, thus creating a circular wall made up of an even number of parts – the amount of wh ich naturally influence the size of the ger . The height and diameter can be adjusted by changing the geometry of the meshes that make up each section. The slanted roof poles, named uni , are the connecting link between the walls and the toono , the crowning halo on top. This comes in two types, differing in the binding between it and the uni : either connected or inserted. The connection is obtained through a secondary flexible structure made of sinew or leather; the insertion, instead, allows for the poles to directly conn ect to the rim similar to the Western mortise and tenon joint (Zhong 2024, pp. 124 - 132). Figure 4 : Mongolian ger under construction. The khana , uni and toono are clearly visible, as well as an entry door. Image provided by Shuying Lin under Creative Commons. 3 . Contemporary applications and future horizons The need for traditional nomadic architecture has sensibly diminished in the 21 st c entury. On the contrary, temporary shelters are still in high demand in areas subjected to natural disasters, war scenarios, or disease outbreaks. The United Nations High Commissioner for Refugees (UNHCR) is t he UN agency mandated to support these types of situations, where people are inevitably displaced. The UNHCR provides detailed instructions to design a functional shelter, such as minimum floor plan dimension s and suggested height, to respond to emergencies. D ULBS 202 6 ______________________________________________________________________________________ 7 3 .1 Current UNHCR state - of - the - art The current shelter design catalogue provided by the organization already enumerates a considerable amount of local - influenced examples developed in different areas affected by catastrophes , with some of the projects representing light solutions. The Tuareg shelter built in north - eastern Burkina Faso in 2012 was developed in such a way that each shelter could be dismantled and moved to another location, owing to the nomadic tradition of the Tuareg people inhabiting the Sahara (UNHCR 2016, p. 30). This scena rio, while partly encouraging from an architectural perspective, is still lacking in the optimization of the traditional techniques ; by rethinking the construction process through contemporary design knowledge – including the advancements introduced by ultra - lightweight building approaches – the efficiency of this architecture could significantly improve , in situations where temporary and permanent solutions could often overlap. Table 1: Material breakdown of the Tuareg shelter developed for Burkina Faso, taken from the UNHCR S helter D esign C atalogue published in J anuary of 2016 Material Description Roof covering material Covering material was provided to provide water proofing and protection from the extreme heat of the Burkina Faso weather. Traditional roof covering material (tanned goat skin) was replaced with plastic tarpaulin due to its unavailability in the local mark ets. Eucalyptus poles These make up the frame of the structure on which the roof and wall covering material are attached with ropes. The vertical members are larger and the roof members are more flexible to give the roof its dome shape. Fixing ropes These are synthetic or local rope used to attach the timber poles for the roof and the walls together and attached the mats to the timber poles as well as the roof covering material to the roof and wall timber poles. Mats Mats are used to cover the walls of the shelter. Straw mats were distributed, although synthetic mats or plastic sheeting are recommended as they last longer and are more resistant. 3 .2 Present - day rethinking of tradition T he fascination that the yurt holds for contemporary architecture research has allowed for several improvements in the building effectiveness of the hut. In the U nited States of America , it has been coopted for tourism in mountain areas with a bigger emphasis on the tensile aspect of the structure, which could easily lead to a general decrease of weight. Its movable capability has been weakened in favour of a better comfort and increased protection from the elements (Apak 2006, pp. 2 - 6). But the issue has a lso been attended to by architectural offices whose goal is not to forget the original nomadic aspect of the buildings. D ULBS 202 6 ______________________________________________________________________________________ 8 3 .2.1 Jero Yurt Scottish architecture studios Trakke and Uula Jero teamed up in 2014 to design the Jero Yurt. Its walls are made of marine - grade plywood, and the roof wooden poles are covered with a waterproof canvas. The elements are developed through a mix of digital and analog ue techniques, allowing for an assembly process that requires no speciali s ed tools. T ensioning straps are applied along the perimeter of the yurt to stiffen its structure, while polyester ropes connect the canvas to the wall panels’ base. This proj ect reduces the final weight of the yurt to about 110 kilograms, compared to the over 400 kilograms of traditional felt - insulated Mongolian ger structures. Its design allows for it to be stowed and carried away in a flat pack Figure 5 : Jero Yurt, designed in 2014 by Scottish offices Trakke and Uula Jero 3 .2.2 Weaving a Home Although she started working on it in 2013, Jordanian architect Abeer Seikaly presented her work “Weaving a Home” in 2020 at Espacio Fundación Telefónica in Madrid , as part of the exhibition “Radical curiosity: In the Orbit of Buckminster Fuller” curated by Rosa Pera and José Luis de Vicente. The design is meant to provide displaced communities with a portable shelter covered by a double - layered performative structural fabric that takes on the shape of a dome. The project is meant to be extremely community - dr iven, sustainable and durable. « The system is composed of durable formed plastic members threaded into a cloth in a predetermined pattern to form a singular ‘unit’. The unit itself is flexible as it folds across its central axis. The degree to which the unit can fold relies as much on th e plastic members as it does on the elasticity of the fabric (the type of fabric would inevitable [ sic ] be one that has both durability and flexibility, and can serve several functions. Spandex blend for the general structure and solar absorbing fabrics serve the function of this project). When multiplied, the geometry and the materiality of the unit work t o create a system that performs similarly to fabric. It can bend on both axis and thus take on a variety of forms, yet maintain a distinct and recognizable presence and structural integrity. » ( Seikaly 2013 , on Designboom ) D ULBS 202 6 ______________________________________________________________________________________ 9 Figure 6: ¼ scale model of Weaving a Home, in its 2020 form, by Abeer Seikaly. 4 Development of an ultra - lightweight shelter solution in the course context During the university course “Design of Ultra - Lightweight Building System”, led by Professor Alessandra Zanelli in Politecnico di Milano, I was able to experiment on this theme with fellow students and group members Dagem Hugegnaw Ayele, Giorgio Parducci, Thu Thao Pham, Elisa Ranzani, Trung Ngan Tran and Caspa r von Werz. The development of our own shelter building led us to design a deployable emergency response pavilion, devised as the symbolic and operational centre for a post - disaster settlement. O ur dou ble - skin envelope serves to provide shade, ventilation and protection from the heat , while it leaves open the access from the sides . The roof’s shape is a hypar , or hyperbolic paraboloid, where although every beam is straight, each element contributes to the curved feeling of the whole. While the design process led us to draw hinges to allow for secure connections between bamboo beams, during the mock - up building process it became evident how, learning from vernacular architecture, a rope binding could prove sufficient, just as in the Mongolian ger Figure 7: 1:15 model of the design. The beams are connected through elastic bands mimicking rope ties. D ULBS 202 6 ______________________________________________________________________________________ 10 5 . Conclusion Historically, the search for the "essence" of architecture has often led back to the lightweight structure. From the 18th - century hypothetical models of the rustic hut to the 19th - century focus on the "four elements" of construction, the lightweight frame and the textile envelope have been recogni s ed by contemporary architectural history (including William J. R. Curtis) as fundamental precursors to monumental architecture. By revisiting these theories through the lens of Kenneth Frampton’s "critical regionalism," we can bridge the gap between ancient vernacular techniques and the universalizing tendencies of modern techn ology, allowing for a more nuanced approach to temporary sheltering. The investigation into ultra - lightweight building systems reveals a profound synergy between historical theory, vernacular practice, and contemporary humanitarian needs. As demonstrated through the comparison of the Kazakh yurt and the Mongolian ger , nomadic architecture is not a primitive stage of development but rather a sophisticated response to environmental and behavioural extremes. U tilizing local materials like bamboo, willow, and felt to create a high - performance envelope that can be transported with ease is what is required in the modern context of global displacement and emergency response. The evaluation of current UNHCR standards suggests that while progress has been made in providing temporary shelter, there is significant room for improvement through the integration of traditional "lightweight" knowledge. The transition from heav ier materials to lighter structural solutions p oints toward a more sustainable and culturally sensitive future for humanitarian aid. The Jero Yurt and the "Weaving a Home" case studies prove that portability does not have to come at the expense of dignity or durabi lity. Reflecting on the course design process for the emergency response pavilion, the most significant lesson was the possibility to shift from mechanical connections to simple, flexible bindings , such as the ones found in traditional ger s Looking forward, the "rethinking of tradition" must remain a central pillar of architectural education and practice. As we continue to develop ultra - lightweight systems, we must ensure that they remain community - driven and adaptable to local climates. The integration of digit al design tools with analog ue vernacular techniques offers a promising path for creating structures that are both technologically advanced and rooted in human history. References Apak K. (2006), Modernization of The ‘Yurt’ Tensile Structures , International Conference On Adaptable Building Structure Frampton, K. (1983) , Towards a critical regionalism: Six points for an architecture of resistance , i n Foster , H. ( e d.), The anti - aesthetic: Essays on postmodern culture , Bay Press , p p . 16 – 30 Laugier M. A.; Herrmann A., Hermann W. (eds.) (1977 ), An essay on architecture , Hennessey & Ingalls, Inc. Malibekuly Z. , Semenyuk O. , Dyisebayev U., Kuc S. (2020), Architecture of the yurt and its impact on teaching young architects , World Transactions on Engineering and Technology Education , v ol. 18, n o. 2 , pp. 225 - 230. Semper G. ; Mallgrave H. F., Robinson M. (eds.) (2004), Style in the technical and tectonic arts, or, Practical aesthetics , Getty Research Institute D ULBS 202 6 ______________________________________________________________________________________ 11 UNHCR Shelter and Settlement Section ( ed.) (2016), Shelter Design Catalogue , UNHCR Division of Programme Support and Management Z hdan ko T. (1966), S e dentarisation of the Nomads of Central Asia, including Kazakhstan, under the Soviet Régime , International Labour Review , vol. 93, pp. 600 - 620. Zhong Y. (2024), A Brief History of the Development of Yurt Architecture , Proceedings of the 3rd International Conference on Art, Design and Social Sciences , pp. 124 - 132. https://www.designboom.com/project/weaving - a - home/