Due to the narrowness of the alleyway (between 3,50m and 4,50m wide), the building site is not easily accessible. And the strict surveillance of the area by its co-owners prevents the parking of delivery vehicles and stocking of building materials. This situation brought us to use materials that could be immediately put together right after being delivered (metal frame, etc...). Moreover, the three adjoining houses were built without foundation: in order to avoid their collapsing, the retaining (breast) walls of the Villa were built using the “berlinoise” technique (phased buried walls). For the foundation walls, we chose the raft (mat) foundation technique in order to evenly distribute the load on all the construction site’s surface. The “concrete box” is used as a floating element to which the metal frame is anchored. To achieve the best possible thermal insulation, the outer surface of the frame has been layered with glass wool and black lacquered aluminium sheet metal. To avoid corrugated ceiling we used formwork in master panel (a high density compressed mixture of wood and cement). This material’s intrinsic qualities enabled us to reduce the upper floor’s ground thickness to a minimum: 5 cm (master panel: 2 cm, soundproof board + waxed concrete : 3 cm.