Nearing its fifth decade of use, the rear extension of Joris E. Maria’s brick villa in Leuven, Belgium, had become functionally obsolete. With a dilapidated roof that leaked and small windows that provided little light, the 430-square-foot space was dim and gloomy. Joris wanted a bright, cozy place to relax with his two daughters, as well as something with a clearer connection to the garden. So he turned to the same architecture firm he had entrusted to update the main house years earlier, ORG Permanent Modernity, led by Alexander D’Hooghe, Natalie Seys and Luk Peeters.

Along with project leader Sanne Peeters and her team, they proposed an inventive solution that Joris, a professor of materials and process engineering, could appreciate: Install a new roof, with a waterproof membrane, atop three walls of the extension, thus eliminating the leaks, while knocking out the garden-facing wall and replacing it with floor-to-ceiling windows and doors for better daylight and outdoor access.

To comply with a new ordinance that capped the height of the extension at 11.5 feet above the ground as measured in the front of the main house, the team specified a thin prefabricated steel plate with a structural load-bearing section that swoops down into the living space in a reverse curvature.

“Aesthetically, we explored how the bump could be asymmetrical and what the character of curvature is.” Alexander D’Hooghe, architect

“Often I have to explain to visitors that the shape has a functional origin,” says Joris. Built off-site by Ateliers Melens-Dejardin, the roof arrived in two pieces and was craned into place in less than a day. Today the asymmetrical dipped ceiling hangs above a sunken living area where Joris likes to unwind. “It’s a totally different atmosphere,” he says, “[It’s our place] for watching TV, reading a book, or just spotting birds in the garden.”