This project was born as a challenge with a friend/client, design a cabin with a max 50 sq mt surface a cost of 1200 €/sq mt and able to accommodate 4 person ( husband, wife and 2 sons). The house is divided in three functional part, services (with entrance/storeroom/bathroom), a unique space for social life (with kitchen, dining and living room) and two small bedrooms. The main structure, a steel cage, has four contact point with the ground, to save time and money during substructures trial. The secondary structure, a metal grid of beams, is hanging on the main structure, in order to avoid use of pillars and permit the maximum flexibility in distribution. To increase the construction process, the walls are of steel stud and plasterboard construction, with two external plasterboard layers and a timber coating in interior faces. The windows are made by an aluminium framework, with double glazing and inert gas fill. A system of aluminium movable grids protect from sunlight the living room and increase house surface, with two loggias in open position. In this configuration the roof is covered by a wooden deck that is achievable with two pegs stairs fixed on the main steel structure; in isolated context the roof can be covered with solar panel to in order to achieve energy efficency