Can you tell us about your early influences? Was there a specific moment or project that made you want to pursue architecture?

Around 12 years old, my grandmother wanted to redo her kitchen and asked me to design it. I did it together with a carpenter. I had to explain things with my hands and little drawn lines because, well, I didn’t know design or architecture yet. My grandmother was very happy with the kitchen, and she even said, “It’s your first project so I will pay you!”

My mother and my father also had a really modern spirit. We lived in a bungalow house, which was redone quite well in the ‘70s. It wasn’t a high budget project, but it was already very modern and minimal. When I was a kid, my mother and my father let me design my own room. I did the same thing as I had in my grandmother’s kitchen, working with the same carpenter. Afterwards, I also did their bathroom and kitchen. After all these little projects, my family and I felt that I should pursue architecture.

To be honest, I was in between fashion and architecture. I had some second thoughts about pursuing fashion, but at a certain point, my mother preferred I chose architecture because it’s more stable. Maybe back in those years, in her mind, it was a more stable career.

For your primary private residence, Pavilion Sestig (2019), you became your own client. What were some of your personal aspirations for the space?

Honestly, the easiest thing for me is to work for someone else—someone else with a strong vision, of course. When I start designing, the most important thing is, first, the plan and functionality, then second, the client’s style. At the beginning, clients never believe me when I say this! But I listen closely and absorb everything they share with me. That’s why each project ends up so different.

The most challenging part here was that Pavilion Sestig was both for me and for Bernard [Sestig’s partner]. Because I was working just for us, it was very nice to have Bernard to talk with. As an architect, I can still be a bit stubborn with my own vision, so it was great when he suggested something I wouldn’t have done.

For example, the house has this big roof. Bernard said to me, “I want to easily be on the roof because it’s full of trees over on the other side. Can you design me a beautiful staircase?” So then I designed it for him. In that moment, with the details we changed here and there, Bernard became a kind of client for me to talk with.

The original structure was created by architect Ivan Van Mossevelde. Can you talk us through how you made decisions to preserve versus renew the structure?

When I look at Van Mossevelde’s architectural plans from the ‘70s and ‘80s, they are already quite close to how I design. It was very easy for me to see what he did and to then bring it into the present, 50 years later, without completely breaking down the walls or changing the architecture. We brought the house into the future with the modern technical features available now. The windows are better, the electrical is changed inside, but the architecture for me is still the masterpiece that Van Mossevelde achieved. I wanted to preserve the house as much as possible. This is not a challenge for me – it’s routine. I work around the space, without touching the original structure, until it feels right. I must say, I’ve been in love with the house since I first saw it 30 years ago.

We also wanted to talk about Penthouse Mulier (2016).

About 35 years ago, an architecture professor of mine used it as a reference project and brought us to the Penthouse on Riverside Tower in Antwerp.

Years later, when Raf [Simons] was at Dior, I was with him in the car going back to Belgium when he said to me, “Peter [Mulier] bought the most beautiful penthouse. Even more beautiful than mine.”

I responded, “Okay, which one? Is it the one on the Riverside Tower?” and he looks at me as if to say, “How do you know that?” Well, it’s because I was actually there years ago! It was amazing to have the chance to see it when I was studying because it’s a private apartment. The past owners, Léon Stynen and Paul De Meyer, were famous Belgian architects and knew my professor since they were all in the same field.

This residence also features some built-in concrete furniture. With furniture design as part of your architectural practice, how do you go about creating pieces that are in conversation with the greater architecture of the space?

If you go into Penthouse Mulier, you won’t see what we added. There is concrete furniture and other new elements we designed, but I don’t want my furniture to pop out and be more important than the existing architecture. I engage in a conversation with the building when it has such a strong identity: my work then needs to be fluent with the existing space.

I must ask out of pure curiosity: I read that Mulier held an Alaïa catwalk in this house. When I saw the very long layout of the house in the floor plan (that looked a lot like a catwalk), I wondered is this the reason it was changed from a 6 bedroom to 1 bedroom residence?

Well, for Peter’s space, we really only wanted one bedroom. The six rooms that existed back in the day for family were removed for the master bedroom. In the end, there are actually two bedrooms with the guest room on the -1 floor. That’s why it’s so empty now.

But then it could be used as a catwalk, voilà! That Alaïa show was amazing.

Talking about your 2018 project, Wallace, there’s something really striking about how planar it is. There’s this cantilever detail and it’s almost as if the house moves into the landscape. It’s a beautiful ode to the original owner of the home, landscape painter Albert Saverys. I’m Interested in how you bring out the subject of the space in your architecture.

Originally, the client had called the office and said, “Is it possible to talk to Glenn? I have a project, but I know he won’t do it.”

The interior of the home was already done, and we normally don’t work around that. If we build a house for somebody, it has to be one cohesive project that includes interiors and exteriors. But because Wallace was so close to our offices, I told the client I would come and see the house regardless. When I arrived there and the outdoor environment was so amazing, I immediately told the client, “Hello. No problem. I will do it.”

We started with a beautiful home, but not something “wow” or particularly huge. The problem was that it was in a restricted area where we can no longer expand the building. But what was possible was terraces, pedestals, and cantilevers. With those, we made the house look double its size without making the internal architecture bigger.

With your consistent application of concrete and building on top of existing architecture, your works are often compared to those of Tadao Ando. I’m curious as to what you make of this comparison.

Ooh la! How chic! Are they now? Who is making this comparison? Well, I love the work of Tadao Ando—it’s impossible to say anything different as an architect. Of course, when you do a house in concrete, it’s easy to say, “it’s very Ando.” I’m very happy with this comparison, but I don’t know if I completely understand it.

My practice comes from a different place. It’s about the existing architecture and the client who brings it to me. This process is really about the space between us—it’s a conversation. I design something that matches the landscape, the existing building, and, of course, the client, who will live in it and need to be happy in it for many years. This is how I see my work in architecture.

What I will say, I do have a client who also has a house in Sri Lanka built by Tadao Ando. The father said to the mother, “I love you so much. What would you like to have?” And she responded, “Oh, a house by Tadao Ando.” At one point, they had the biggest private Tadao Ando home ever built. And now, I’ve done a few homes for them as well. One is Retreat Pringiers on the coastline of Belgium in Ostend. This house is completely concrete inside and out, so I can understand if people see this and say, “oh it’s a bit Ando.” But these clients are really in love with concrete.

On the note of concrete, do you find that there are certain materials or techniques you often find yourself gravitating towards on your projects?

We use a lot of natural stone. In Pavilion Sestig, marble had already been installed back in the ‘80s but we took it out. With the loud white color and the big nerves, it was too ‘80s. The original architect, Van Mossevelde, was very ahead of his time when he chose it, but for us, it was too indicative of the era. Instead, we used a sandstone that went well with the color of the concrete.

In a building with a concrete exterior, most of the time, it’s more beautiful to also have concrete flooring and concrete elements continue into the interior. Though if we are using stone, I love gray travertino, specifically, Travertino Titanium. It’s in Peter Mulier’s kitchen.

This gray Travertino is great because a lot of people initially think it’s concrete, but it adds another feeling. Living on and touching natural stone is just a different experience from concrete.

It’s interesting to see how so many of your projects build atop and renew the existing architecture in the space. If you were asked to renovate a project you worked on 10-15 years ago, what would you focus on?

When I take on a project, the materials and products should last as long as possible—that’s my ecological approach to architecture. Even though renovations often result in a lot of waste, when we bring in new architecture or interiors, the goal is to make them last for years to come.

I believe that’s the most ecological thing you can do with a building. It’s not really a building if, after 10 years, you have to throw it away and build a new one.

The buildings we work on are old buildings with strong architecture. That means you can renovate them, and they don’t need to be completely demolished. If I were asked to renovate a project, I’d focus on making functional improvements and expanding the space, rather than just updating it because it’s no longer good enough.

So yeah, voilà!