Sabzevar is a small religious city with no remarkable public entertainment space, and people’s activities are limited to their houses. In Sabzevar, residential development does not address quality; Houses provide basic living spaces: living rooms, bedrooms, and kitchens. They don’t often have terraces, and yards act as parking spaces. One of the main design strategies was to provide internal interactive spaces for the family to increase shared time and to make up for the lack of urban public space. So, the program of the original separate four-floor-apartment was transformed into a pack of hybrid living spaces surrounded and scrambled with interactive functions. Vertical access became the main target in organizing the whole structure through tying the functions and floors while providing communicating spaces. Consequently, the staircase was exploded and transformed into a vertical corridor including a lobby, a gallery, terraces and a sports area, and finally bringing you to the duplex of the parent’s house. Therefore, the vertical access acts as a walkway chamber and grows through the various spaces of the house. The variation and growth of the interactive and transitional space, gives the house a kind of addressing, a description of the physical location of each space. The spaces and places are named and characterized by different family events, activities and living scenarios. Now the family has a new vocabulary to call and name different places of the arc house. The arc form of the complex increases the sense of giving an address in various levels. From the second floor the walls start to shrink, curve, and angle from the sides which represents different heights of the complex. Ultimately the arc is completed at the top of the project and covers the duplex. The arc ceiling represents the sky, indicating that there are no more habitable floors above it.