Cornerstone is a restoration and addition project of two buildings on a vast lot on the Plateau Mont-Royal. A few elements in poor condition due to several years of abandonment will be demolished to preserve and restore the main volumes of the buildings. The interstice between these latter and the vacant space overlooking Saint-Denis will host the extension of the corner building. The addition will be build around a green courtyard with a common terrace. The ground floors will be dedicaded to commercial spaces. On the upper floors, a variety of units will welcome a diversity of tenants. A rooftop terrace on the addition will offer an exterior common space and views on the roofs of the Plateau and view of the Mount Royal.