The existing suburban house design consists of a cellar, living space and bedrooms on the ground floor, and an unoccupied attic. The room proportions are similar in size. The program requires the construction of large new spaces. The owners needed to double the living surfaces. The extension lies in the border area next to the neighboring property. Because of building code restrictions on building near property lines, the extension was created on the second floor only, freeing the space underneath. Its characteristic shape fits the junction between the gable roof of the main building and a template that corresponds to the height of the house and enables the creation of mezzanine spaces. A buffer room is included in the design between the children's rooms and the master bedroom. This space allows access to the garden and defines the areas appropriated by the office and the multifunctional space. The new part of the house constructed with a wooden frame and a wooden exterior contrasts with the existing building.