Located in the historical center of Voiron, an old degraded collective building is the object of a future heavy energy renovation. On this occasion, the complete transformation of the housing typologies is planned. Currently composed of a T3 per level, the objective of the owner is to divide these floors. From this observation, we have sought to design T1bis and T2bis that can find the quality of volumes and surfaces initially present. We designed apartments with large sliding doors, which allow the living rooms and bedrooms to open generously towards each other. The spatial optimization of the kitchens and bathrooms increases the impression of space available for the living room and the bedrooms.