A renovated 18th-century building is now the beating heart of a co-housing project in Leuven, Belgium. Distinct from the development’s cork-clad apartment blocks, the pitched-roof structure once housed a café called “De Sijs,” which became the new project’s namesake. Beyond the charm of its restored facade, the neighbourhood fixture is the inviting face of OFFICEU architects’ pragmatic and innovative solution to urban housing. The three volumes are linked by an L-shaped circulation axis, along which are located the entrances to the flats and the shared spaces — a move that maximizes residents’ interactions and strengthens their sense of community.

The De Sijs co-housing project comprises three structures: two cork-clad apartment buildings (with semi-underground parking) arranged around a heritage building, which is newly restored and used as the central hub.

The project is the result of an open competition organized by the city and the future inhabitants and assisted by Cohousing Projects, a Belgian organization that acts as a consultant and investor (through a cooperative structure) for groups of people who want to build such projects. The future inhabitants had acquired a ground lease from the city, which made any development contingent upon its adherence to a sustainable design.

The pitched-roof heritage structure dates back to the 18th century. OFFICEU’s proposal to renovate and integrate it into the complex helped the nascent firm win the project competition.

OFFICEU was selected in recognition of its proposal’s integration within the neighbourhood and special attention to organic materials. Also impressive is its broader philosophy, which generates circulation throughout common spaces and centres the firm’s theme of urbanity. “It’s what the ‘U’ in ‘OFFICEU’ stands for,” says architect Pieter Thibaut, co-founding partner at the practice. “It refers to living in a city while engaging with everything that comes with it, and, most of all, doing so sustainably. It’s about making a building future-proof and allowing different elements to work in unison.”

In this uplifting, soft-hued suite, a mint-green kitchen — and its mix of tile and wood finishes — exemplifies the eclectic interior design achieved by OFFICEU and the project’s residents.

Input from residents, many of whom are also co-owners in the cooperative structure endorsed by Cohousing Projects, was a major consideration in the spatial program. “A co-housing project is different from a standard housing project,” says Thibaut. “The collective impact must always be considered in the decision-making.”

The fingerprints of De Sijs’s inhabitants can thus be found throughout. In the restored building, they helped to create a central hub outfitted with intricate communal spaces that encourage both privacy and collectivity. Here, residents share a dining area with a kitchen and large terrace, along with a cozy living space overlooking the garden, a fully equipped guest stay, an atelier and a quiet co-working space with a view of the city — a unanimous request, since many residents work remotely.

The future residents of De Sijs were involved in the design of their apartments. To maximize the usable space, the architects came up with some clever moves, such as positioning a desk beneath a staircase.

In each of the two housing blocks that flank the central hub, six apartments (ranging from compact studios to three-bedroom duplexes) pose bright, spacious living quarters linked with a generous private terrace facing the sunny garden. Residents were invited to customize their spaces, which allowed the firm to push the bounds of a typical apartment, in one instance using sliding walls to create a multi-functional yet entirely open-concept home. “As interior architects, we had the opportunity to research ways of living on a small surface with maximum natural light, open space and flexibility, and to serve the residents’ unique interests,” says Thibaut. “Even the bathroom is a space that can be opened, closed or subdivided depending on the use, so a family of five can brush their teeth together in the morning but use the niches to easily access privacy when needed.” OFFICEU’s preference for organic materials makes for a soft colour palette and gentle framework for everyday life.

The buildings themselves were constructed with a skeleton of wooden beams and columns and insulated with cellulose. The cork panelling that clads the facade is made with compressed leftovers from the cork industry; it’s tactile, breathable and both water- and rot-resistant. Because of its high density, it also buffers sound better than traditional insulation and protects the building from overheating. An elegant concrete staircase, which leads from the central hub’s terrace to a semi-underground parking garage in one of the apartment blocks and the ground-floor apartments in the other, doubles as a lush green garden.

For Thibaut, the task of accommodating the varied needs of De Sijs’s inhabitants is satisfied by the project’s functional outcome. “When I pass by the site, I’m happy to see activity and buzz,” he says. “This project marks our beginning as an architectural design firm, and it’s rewarding to feel we’ve achieved our vision.” He believes, however, that his design should not be considered finished; it will evolve over time, adapting to its residents rather than imposing a way of living on them.