In a trapezoidal plot in the so called “Porta Palazzo” area in Turin, twenty-seven small size flats, common spaces, a restaurant and three shops were created from the renovation of an historical building and the construction of a new one. The project path was complex due to the many constraints on the set of buildings, and the construction phase took two years. Every project solution, in term of architecture, structures and systems, aimed at energy efficiency and functionality. The barrel vaults in the historical building were reinforced by lightening and rebalancing forces. Whereas the renovation was not possible, due to the deep decay and to the particular shape of the building, new structures of steel or wooden elements were erected by using dry techniques.