ellipsearchitecture
Lausanne

Humble Leanings, Cyclical Processes

Founded in Lausanne in 2018 by Mattia Pretolani and Yannick Claessens, ellipsearchitecture approaches architecture as an act of careful transformation rather than creation from scratch. The studio, whose name reflects both humble service and poetic possibility, specialises in adaptive reuse and thoughtful densification of existing structures. Both partners bring academic rigor from their teaching at EPFL, informing projects that work sensitively with the industry. Their design process begins by listening to materials and sites. Natural substances like stone dictate structural solutions, while community knowledge shapes participatory projects like the Belle-Idée kiosk. This material intelligence extends to unexpected collaborations, as when working with ornithologists to create bird habitats on human-altered lakeshores. At every scale, from rustic renovations to urban interventions, they demonstrate how bio-based materials and existing conditions can yield fresh architectural solutions without demolition. What emerges is architecture that balances practical adaptation with quiet poetry, where regulatory constraints become creative opportunities, and where each project's "ellipse" of unspoken potential guides the design. The studio's work ultimately suggests that the most sustainable architecture might be that which reimagines, rather than replaces.

MT: Mattia Pretolani | YC: Yannick Claessens

 

A new wave of practices

MP: In response to your remark on an emerging Swiss tendency in architecture, I would say that so-called styles are often defined in hindsight by oversimplifying a much larger spectrum of common traits. In the present we can recognize them, but they are somehow on the edge of existing/non-existing. If I look at Instagram profiles of emerging practices, I can probably tell they’re from an alpine region, even if many architects involved are from abroad and bring (luckily) their own set of influences. 

YC: It is more about their approach to design and process.

There’s a greater awareness of ecology—questioning what exists, what can be reused, and what can be optimized. This shift is also happening in schools, where the focus is more on reusing existing structures and materials rather than creating the most striking image, which was more common in the early 2000s. 

MP: Now there’s a renewal of baby-boomer buildings public buildings across Switzerland, raising new questions. This renewal gives the impression that a new generation is starting now, but that doesn’t mean people weren't starting 10 years ago as well.

YC: Indeed, in the early 2000s Switzerland decided not to expand outward but to densify and reconsider existing sites and buildings. It took time for these laws to take effect. When we started, there was still some open land, but we increasingly found that there were no longer blank slates. We were always dealing with sites that had preconditions or even existing buildings. That’s a key characteristic of our generation—we’re thinking about how to deal with existing structures. Sometimes it's worth keeping everything, sometimes not, but our approach is to question first, then provide the best answer.

MP: People who started before us were still in the shadow of the early 2000s and the 1990s image of the Swiss architect, which was shaped by these ‘superstar’ architects. For 10 or 20 years, that shadow was still there. Many people were trying to replicate that because it worked. But I think our generation is too far removed to feel that influence—we weren't their assistants, we weren’t directly connected to them. And, academia has been changing. All these factors are creating a wave that many practices are riding, and that's why we can start to trace a line connecting all these points.

 

Architects’ evolving role

MP: Some influence on our profession comes from the top—European regulations and policies being applied in Switzerland, including political decisions like the CO2 reduction targets, which affect every sector, including construction. But while that might be seen as the primary movement, I’d say there’s also a strong feeling coming from the bottom, especially among the younger generation. There’s a certain anxiety about the future, and that drives change. You could say that things are shaped from the top down, but I think it goes both ways. The top-level decisions validate what’s happening on the ground. For example, if I go to a client and suggest using sustainable materials, the fact that public institutions encourage these materials gives them legitimacy. There are also resources and grants available for research on these subjects, which supports our efforts. People might have been experimenting with similar ideas 30 years ago but without validation or support, so their work remained small and largely unnoticed, though it existed.

YC: The schools play a big role in this. They're highly regarded by the public. If we go to a client and say we’re teaching at EPFL, they immediately recognise our value. And when a school is respected by society, the ideas it teaches also become accepted. Schools listen to what society is discussing, and they help validate political ideas through technical or theoretical work that feeds back into practice. For me, as a practitioner, when we talk about what we’ve learned at school, people don’t immediately dismiss it. There isn’t this divide between an "elite" doing something disconnected from the rest; it feels more connected.

MP: The profession has become more humble—I'm not talking about salaries or the number of architects, but perception. It’s no longer seen as an elite profession, which I think allows architects to connect with a broader part of the population. We’re in a postmodern crisis where we know architects can’t directly impact political issues or society’s problems in a sweeping way. But I also think architecture has been too constrained in recent years. You’re often given a brief, and you’re not allowed to challenge it. You’re asked to design a school, for example, but the parameters are already set, so you can’t rethink what a school should be. Architects have lost agency in many areas. But we still have the power to shape certain things, and I believe some of that influence has to come from the bottom up—from architects themselves, who are also part of the population. We can play a role by making choices about how we build, what projects we refuse, and what materials we use.

 

Learning on the job

MP: I see a problem with architectural education in that we spend about seven years learning, but are we being taught a job, or is it more a way of seeing the world? I tend to think it’s the latter. But if we treat it as job training, then after seven years, we should be ready to work. Yet, when we finish our education, many of us across Europe don’t feel prepared or confident enough to take action. I don't mean that architectural education should be orienting students towards a neoliberal market-driven profession, but this ambiguity needs to be addressed. Seven years should be enough to feel prepared, otherwise, you end up endlessly waiting—like in The Desert of the Tartars, constantly preparing for something that never arrives. Some think, “If I get two more years of practice or pass a business management exam, then I’ll be ready.” But we believe you learn by doing. In Switzerland, architects historically didn’t have the same kind of academic training as in other European countries. Instead, they would intern at an office and learn on the job. After two or three years, they’d start designing projects. Feeling legitimate is crucial, and education plays a key role in this. If education includes hands-on construction practice—not necessarily traditional methods but experimental approaches alongside concrete techniques—it would help students apply these skills directly in practice. Of course, there’s a lot to learn, and we were naïve when we started, but you grow organically. 

YC: Starting with no pre-established mindset makes it easier to think differently and to trust professionals, like artisans, in their expertise. At first, we knew we didn’t have all the answers, so we couldn’t provide perfect details. Sometimes our instructions were incomplete or even wrong—it was more about giving an idea or a framework.

So you end up asking and learning from them. Over time, you gain experience, and now our approach to projects and construction is different. We don’t see ourselves as these grand architects who know everything and dictate commands from above. We’re part of the team, part of the environment. We listen and learn, which has allowed us to do things differently. 

 

Experiences on site

MP: We had a humbling experience with our first projects, which we built ourselves with help from friends and clients. It was a rustic stone construction in the mountains of Ticino. There was no road access, only a path, so we had to carry everything up on our backs. We camped there for three months, with a water source 100 metres from the site, no electricity, and only a small generator and solar panels. The clients were young, like us, and it was a learning process for all of us. We made mistakes but learned from them by working directly on-site. That hands-on experience taught us how difficult construction actually is. Many decisions were made on-site rather than through drawings. We also asked the craftsmen for advice, relying on their expertise. For instance, carpenters know more about carpentry than architects, so we would ask them how to do things best. We had our vision, but we were open to their input, which saved us time and created a better working environment. They didn’t feel like we were imposing something unreasonable on them. And while we had some key ideas, like ensuring the walls were breathable without steam barriers or focusing on specific aesthetics, we were flexible with other details as they arose on-site.

YC: That worksite felt like a microcosm. We had water to drink, food to eat, and materials to construct. It became a kind of laboratory for primitive techniques—running water, dirty water, and a bit of electricity from solar panels and a generator. That was it.

MP: We tried to use as many local materials as possible. For example, we used wood from the region, brought it to the carpenter, and then used it at the site. It was an adventure—one we wouldn’t repeat on every project, but as a start, it was humbling. It made us truly understand the effort behind every task, especially without the help of machines.

 

Guided by principles and cooperations

MP: Ellipse represents the idea that architecture can be anything; it's a humble service like any other. But the ‘ellipse’ itself symbolises something we don't always talk about, something more that guides our work. 

There are many aspects we value. One is working with what already exists, avoiding demolition when possible, and seeing materials not just as resources but as something structural and form-defining. For example, when we work with stone or earth, those materials guide the entire process, including the form and structure. There’s a fragility in these materials that requires skill, which in turn shapes the project. We also emphasise participation on-site. Whether it’s involving local communities like we did with the kiosk in Belle-Idée or in the rustic stone project, or collaborating with landscape architects or artists, participation is key. For example, we designed a structure on a lake specifically for birds to rest because there were fewer places for them to land due to human activity. We consulted ornithologists and were concerned it might not work, but it did, and that success showed us that architecture can stem from many unexpected sources.

We’re also heavily involved in ecological construction. We’ve even co-founded a cooperative, Origo, which changes the relationship between the working site and the people involved.

YC: The idea behind Origo is that we’re not traditional architects managing workers from above. Instead, we collaborate and share risks equally. Working with geo- and bio-sourced materials carries certain risks, and clients or cities sometimes need risk-takers. For example, using earth may be easy for a small pavilion, but for a larger building, it’s complicated. Origo was created to share the risk and knowledge required to use these materials.

MP: The main goal of Origo is to bring together different skill sets—craftsmen, engineers, and technicians—to change the way we approach construction and push forward research and education on bio-geo-sourced materials. Origo and Ellipse are closely connected. If we see a project within Ellipse that aligns with Origos’s goals and the client is on board, we’ll shift it to Origo, and vice versa.

 

Potential in regulation's ambiguities

MP: Part of our work involves navigating the grey zones of regulations. Often, we work with exceptions and shift the rules when managing renovations. This is essential because many regulations are designed for new buildings, not existing ones.

YC: And when you apply new regulations to older buildings, it creates ambiguities. Our process typically involves looking at the site, reviewing the regulations, and identifying where there’s room for exceptions or where conflicts arise.

MP: This process also shapes the project itself. For instance, in one of our recent projects, we integrated solar panels into the facade rather than placing them on the roof, which is more common. The project may appear functionalist at first glance, but the aesthetic emerges from the materials and the structure. There’s a link to vernacular architecture but with a twist. We joke that it’s a ‘hard style’, focusing on tectonics—the physical structure and weight of materials.

YC: We approach architecture in a way that is truthful to the materials. People can recognise authenticity in materials like stone or earth, which carry a sense of place and origin. This truth in assembly is fundamental to our work.

 

00. 250114 ellipsearchitecture ellipsearchitecuture  ➡️ ellipsearchitecuture, Team. Ph. Courtesy of ellipsearchitecuture1 ➡️ (000) earth pavilion. 2017, St. Gallen. Ph. Philip Heckhausen5 ➡️ A(016) 2 lunes. 2021–2022, Yverdon-les-Bains. Ph. Legros Studio6 ➡️ (018) individual nfrastructure. 2021–2022, Savigny. Ph. Julien Heil7 ➡️ A(038) ar-ko. 2021, Vernier. Ph. Baptiste Coulon9 ➡️ C(061) le cercle des oiseaux. 2022–2024, Lausanne. Ph. Michael Hartwell






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