The originality of the project stems from the typological specifics of the existing house, which is a single-family semi-detached house. Unlike the typical attached duplexes found in Montreal, which have party walls on both side lot boundaries, the semi-detached house only shares a wall on one side.

This asymmetry is further accentuated by the presence of side openings and a pathway leading to the backyard. The addition thus takes advantage of these conditions to propose a dynamic geometry that aligns with the property line on one side while opening up to the side setback on the other.

The roof overhangs, which also serve as railings for the rooftop terrace, extend toward the backyard as well as the side circulation areas. They follow a freeform trajectory, yet establish points of connection with the rectangular shape of the addition.

In cross-section, the steps that articulate the main space emphasize the separation between the dining area and the living room, providing the latter with greater ceiling height and helping to reconnect the house to the ground of the terrace and backyard. The copper cladding not only emphasizes the distinctly new nature of the addition, but also creates a cohesive chromatic ensemble with the existing brown brick.