Doma is the small room, at the rooftop of a polykatoikia structure, which was initially constructed either as the end of the staircase or as the top of an elevator shaft, is horizontally extended, often illegally, onto the shared rooftop terrace, transforming into a small studio or an enlarged storage room for family members. The widespread arbitrariness of expanding the rooftop structure onto the communal terrace seems like an obvious move in the case of the family apartment building, as the spatial needs are high and there are no objections or controls from other co-owners.