The client is a long-time friend with whom we have been working since years. He asked us to imagine an extension, adjacent to his office located in a house from the late 1930’s, in the green suburbs of Brussels. The existing house, surrounded by a beautiful garden, would not allow for endless possibilities due to the size of the plot and the strict urban regulations. We chose to create a narrow construction to fill the void between the existing house and the neighbors. Although the option might seem odd—the space would now occupy a narrow gap— this allowed us to benefit from the best orientation and views towards the garden without loosing a much needed surface. The architecture is radically different than the existing adjacent building, yet respectful of the context. The new volume consists of a minimal, elegant black steel and glass construction. Reminiscent of modernist glass pavilion structures, the open plan on the ground floor is enriched by the continuity of the aged blue stone floors inside and outside.