The celebrated Belgian architect Glenn Sestig first set eyes on his home – a modernist pavilion in Belgium’s genteel, green suburb of Deurle when he was still a student. Out on a weekend walk with his parents, who lived in nearby Ghent, they came across the place.

He was immediately struck by the rectangular concrete construction, with its gently curved corners and floating aspect, and realised he needed to know more. “I wanted to go inside, so one day I knocked on the door and asked to take a look around,” he recalls. But the owner said no.

Sestig, never stopped dreaming about the house. Then one day, in 2017, he learned that the owner had passed away and it was up for sale. “I thought: oh my God. Here we go. What do I have to do? Because this [house] is [in] one of the most expensive and beautiful parts of Belgium.” The asking price was too high, so Sestig wrote a letter to the grandson of the owner. “I explained that I was an architect and I wanted to renovate it [using] the same idea of the original owner. I offered my price and gave him 48 hours to say yes or no. Forty-six hours later, he called and said, ‘let’s do it’.”

The house was designed in 1972 by Belgian architect Ivan Van Mossevelde for Roger Matthys, a neuropsychiatrist, and his wife Hilda. They were prolific art collectors and the house was created as a gallery that you could live in. It was one of very few modernist buildings in the neighbourhood. “It needed 70 signatures from neighbours to put a structure like this in this area,” says Sestig of the huge 1,000 sqm single-level living space. “Every penny went into their art. It had white walls for the art and [white] carpet. It was very Seventies.” But the bones of the house were exceptional. Sestig began a sensitive restoration with his partner, the artist and creative director Bernard Tournemenne, who works with Sestig’s practice on creating and developing atmospheric palettes of textures, colours and tones. In 2019, they moved in.

The front door leads into a sunken gallery space, where ‘god rays’ shine down from skylights on to a Zaha Hadid Moraine sofa and an original 3m x 8m Sol LeWitt mural, drawn with pencil on to the wall. It was installed by the artist in 1972 for the previous owners and has been carefully preserved by Sestig.

The windows that were there when he bought the place were black to protect the art. Sestig replaced them with modern glass, which “brought the nature inside” and offered views of the landscaped mounds and plateaus he created in the garden. Those Seventies carpets were swapped for grey travertine (one of the architect’s favourite materials), which creates subtly coloured zones in the open spaces. “It breaks all the minimal lines so it’s more natural,” he explains. The kitchen, designed with Sestig’s bespoke fixtures and fittings (taps are a particular passion), is in its original corner position, as is the dining room. The position of a fireplace was moved to better show the curved edges of the building and the previous owners’ office has been turned into the couple’s dressing room (with cupboards full of Sestig’s enviable collection of Raf Simons and Matthieu Blazy’s Bottega Veneta – both designers are friends).

There’s only one bedroom. A corner suite is dominated by a huge bed and a sculptural lamp designed by an old art-school friend, the designer Laurence Kluft. When Sestig visited her studio, he found that she’d created more than 100 pieces so he put her in touch with a gallerist who arranged a show and sold the lot. “I like to connect people,” says the architect, modestly. Sestig is an early riser but he’s often woken at 5am by his white, blue eyed cat, Tanit, (a deaf stray he rescued from Ibiza). Like everything in the house, she’s a beauty – and her world is also well-designed. He keeps her food stashed in a hidden cupboard disguised as a plinth in the kitchen.

A suite of offices runs down one flank of the building, where Sestig hosts client presentations – the house is as much a showroom for his architectural approach as it is a home for him and Tournemenne.

Sestig’s biggest architectural intervention is the floating staircase that rises from the central courtyard, which he approached with absolute respect for the original. “I wanted to [be able to] go on the roof easily for maintenance but I wanted something that didn’t touch the architecture, so I left it not touching the walls. There are no holes in the wall. No damage. This is my way of thinking when I approach strong architecture with interventions. I don’t want to touch the original. I try not to. I give the opportunity to the next person to bring it back to how it was if they want. If I’d found this house and they did the wrong staircase and there were all kinds of holes in the walls I would have been devastated.”

Contemplating the life the house may have beyond him is ingrained into his, long-term architectural point of view. He believes in building things well and to last. “It’s more expensive to do it really well – that’s true – but in the end I don’t have to do anything with the house for 20 or 30 years.”

Sestig took the same approach for Pieter Mulier’s brutalist penthouse in Antwerp. He designed the interior, where, earlier this year, the creative director of Azzedine Alaïa held a fashion show, with models stalking the concrete corridors and guests reclining on his black leather bedspread. “We didn’t touch the architecture that was there, we just made it stronger and took off things that came in during the [last few] years. There were walls that were plastered and we took those out. Pieter is in love with concrete,” he says. Sestig loves it too, but he also values luxury and comfort, with a preference for the organic beauty of natural stone. When he started his practice, Pawson minimalism was all the rage but Sestig and Tournemenne developed their signature style of contemporary elegance, which combines sensuality, colour and luxury with strong architectural lines and clean spaces.

Sestig’s house boasts several pieces he designed himself, from lamps and light fittings to chairs and even a glass cloche from a recent homewear collection. The Belgian loves sourcing furniture and objects from galleries and auctions and there are notable pieces by several architects. As well as the Hadid sofa, the living room boasts two others by Carlo Scarpa (one of his favourite architects) and an Oscar Niemeyer bench rests in a corridor. A pair of handsome 1950s concrete chairs are displayed in the living room. Originally created as mass-produced Italian street furniture, the designer is unknown.

From left: The view from the entrance hall to towards the kitchen, Sestig in his entrance hall, a sub-woofer integrated into the coffee table, the living room with two Carlo Scarpa sofas, samples from the materials library.

The home is sleek and organised but not spare. He prefers sculptures by Guy Bareff and Faustino Aizkorbe to largescale paintings and favourite objects are choreographed into interesting displays. There’s a surprising diversity to what makes the cut. A Gio Ponti tile, travertine bowls from cult Italian 1970s brand Up & Up and a miniature Alexander McQueen leather skull purse are among the objects that have pride of place. He uses old Tom Ford candle jars as bedside flower vases. There’s a sense of decisiveness and fidelity to his approach. “If I like it and it’s okay, we don’t change it,” he says. Once something is settled into a space it stays, although, he notes, “we are nearly full”. Perhaps the need for more space is just the excuse he needs to buy the architectural gem he’s got his eye on in his beloved Ibiza.

Sestig’s design talent emerged early. At only 12 he fashioned his first space: his own bedroom. “The look was dark grey, very minimal. There was a turquoise sofa and a light grey carpet,” he recalls. Remarkably, the room remains unchanged in his parents’ house. He considered interior design but his mother encouraged him to study architecture at the Henry van de Velde institute in Antwerp.

There he gravitated towards the fashion students. “I didn’t like the architects. Not fun enough. Well, not my kind of fun,” he says. In the late 1980s and early 1990s, Belgium was a hotbed of both directional fashion and era-defining clubs and music. Sestig was immersed in the scene. He still loves clubbing, especially in Ibiza. “I love it, it keeps you young in the mind. Our work is heavy. Architecture is intense, but when you are in the club you are totally free.” He counts many musicians and DJs as friends and clients (Honey Dijon was a recent house guest and he has designed a Studio in Ghent for 2manydjs, aka electronic collective Soulwax), which explains the sub-woofer he’s integrated into the mirrored coffee table designed for his living room.

Sestig’s breakthrough came shortly after graduating in 1999. He and Tournemenne had just got together and were working on the design for their own apartment. Six months later it was given a 10-page cover story in Elle Decoration. The commissions rolled in after that. He’s since designed stores for Raf Simons and is currently working on a large hotel project in Knokke and a house for one of the original Antwerp Six designers, Ann Demeulemeester. He’s not the kind of architect to create something that looks good from the outside but doesn’t function within. “I see architecture as something from the inside, from an intuitive feeling of people together,” he says. Indeed, his approach is one of openness, consideration and empathy for those who will use the spaces he creates.

He is a great reader of people, quickly divining their tastes and needs. When working with a new client, he likes to spend an afternoon with them, shopping, walking the streets or going to a gallery, after which he knows their taste exactly. “It’s very intuitive. I will feel what you like. I tell clients, ‘I think you like this’ and they say, ‘how did you know?’ I go as much as possible into their ideas and their way of life because they have to live in it. I don’t. I’m happy to make it amazing and beautiful and if they are happy they will come back. That’s my motto. I just want them to come back.”

One regular visitor to his home is the building’s original architect, Ivan Van Mossevelde. “He comes here once or twice a year. He says, ‘Glenn, you really did my house well’.”

Taken from Issue 58 of 10 Men UK – ELEGANCE, GRACE, BEAUTY – out NOW.

Photographer VALERIE SADOUN
Text CLAUDIA CROFT