This month I interviewed engineer Julian Lienhard, partner and founder of str.ucture and head of the structural design chair at the University of Kassel. We talked about his academic biography, working at SL Rasch, ultralight backpacking, and his experiences at the Expo in Japan. In our conversation it became obvious that Julian found his calling and has this immense amount of energy and motivation for the topic of lightweight architecture. This episode was moderated and produced by Leon Hidalgo. lllightness is a reader-supported publication. To receive new posts and support my work, consider becoming a free or paid subscriber. The following article is meant as an informational extension of the podcast episode: In 1998, Julian had his first design-build experience in a high school project of building a climbing wall in South Africa. He found a fascination for the matter and decided after finishing high school to go and study architecture or structural engineering. By chance he landed in the engineering studies in Stuttgart and there met Juergen Hennicke in the Lightweight Institute, the last colleague left of the Frei Otto times. The unusual building of the ILEK intensified his fascination for architecture and specifically for the lighter kind. Later in his third year of studies, by coincidence he stumbled into a job at Bodo Rasch’s office. There he worked nonstop on the famous Medina Umbrellas together with another freelancer, who later became his office founding partner. Lightness¹ the quality of having little weight Being a passionate climber, the niche of ultralight backpacking was a natural fit for Julian. With his climbing partner, discussions arose frequently about the best lightweight equipment. While his partner mostly opts for highly specific tools, Julian prefers multifunctional ones that save weight but have recently begun to fail. These categories of lightweight design he also finds in architecture. He further explained that there are three types of lightweight design: system lightweight design, which involves creating structures with multiple uses and considering their entire life cycle; material lightweight design, which produces high-performance materials but often makes recycling or reuse significantly more difficult; and structural lightweight design, which focuses primarily on optimizing geometry. Julian believes that we need fatter structures and thereby more thermal mass in order to remain resilient in the face of climate change. However, when it comes to other safety measures—such as fire protection and noise insulation—he argues that we have gone much too far in adding mass. De-norming these aspects and reducing the millions of tons of material extracted might be worth accepting a slightly higher fire risk and the occasional sound of a neighbor’s voice. Having recently worked on the German Pavilion for Expo 2025 in Japan, he came back shocked by the overall quality of many of the structures, which barely followed the idea of combining form and structure. The most striking example, he noted, was the Qatar Pavilion: from the outside, it suggested an elegant membrane structure, but inside it revealed itself as a heavily over-engineered assembly of massive steel beams spaced every three meters and clad in plastic timber imitation. While in Japan on an excursion with his students, Julian also visited one of his favorite works: the remote Miho Museum with its unique hybrid suspension bridge. He was struck by the place’s extraordinary beauty, even as he noticed - and discussed with his students - certain inconsistencies in its structural logic. For Julian, intense debates between architects and engineers are essential to creating truly beautiful structures. lightness² the state of being light in color or shade He recalled with a certain pain his first experience working on an Expo, back in Shanghai in 2010. For the Norwegian Pavilion, he and the engineers from sweco developed a wood–membrane hybrid structure designed to be dismantled and reused after the event. After intense material sampling the client chose the far more expensive PTFE fabric for the membrane, beautifully translucent and offering a pure white that PVC-coated polyester simply cannot achieve. But when the clients realized at the opening of the expo that the interior was too bright for the exhibition, they turned (without asking) to the only paint that can adhere to a Teflon-based membrane and coated the entire roof. From the inside, every brushstroke was visible, and the lightness and elegance of the material was lost, before Julian and his team could suggest an alternative solution. But when the clients realized the interior was too bright for the exhibition, they turned to the only paint that can adhere to a Teflon-based membrane and coated the entire roof. From the inside, every brushstroke was visible, and the lightness and elegance of the material was lost. In another more recent project at Str.ucture, Julian and his team inserted a new ceiling into a former church to convert the space into a day-care center. The ceiling consists of inflated ETFE cushions, which create a delicate play of light as the colors of the stained-glass windows softly reflect across the surface of the bubbles. When discussing the potential span of inflatable structures, Julian defended what is often dismissed as a utopian vision: Buckminster Fuller’s proposal to place a dome over Manhattan. Fuller’s idea was based on a simple premise: While the dome itself would cover a vast area, the total surface of the buildings beneath it was roughly 80 times larger. By enclosing the city, all of that surface would no longer need individual weather protection, resulting in enormous savings in material and mass. lightness³ being carefree or feeling without burden Julian recalls a sense of lightness when working with his wife, an artist who explores physical phenomena. He vividly remembers the moment they released a weather balloon into the sky, fitted with several GoPro cameras and destined to burst at high altitude. Using GPS tracking, they eventually recovered the balloon and viewed the footage through a Google Cardboard—an early prototype of VR glasses. Looking back, he feels that his recent work on the German Pavilion with LAVA Architects was especially meaningful, in some ways closing the circle that began with his first Expo dilemma. The age of lightweight design as pioneered by Frei Otto and his generation may have faded, but its fundamental ambitions have not disappeared. Julian and his office are keeping its core values alive through new tools and strategies that reposition minimal impact design as a viable philosophy for the current state of our built environment. Get full access to lllightness at lllightness.substack.com/subscribe
