This final paper shows the process of devising the positions and functions of rooms in family houses. The final paper consists of two parts. In the first part, there is an introduction to the topic of family houses, types of family houses, and examples of family houses which are analyzed. Its divisions and the necessary functions of the rooms are supported by examples of family houses in Croatia and foreign countries. The examples are analyzed and described in such a way that the reader understands the way of designing and the meaning of rooms in a family house, and why functional minimums are important to us. The second part of the final paper presents the guidelines, a detailed description of the functions of the rooms and the conceptual floor plan of a family house intended for a family of four. The project assignment was designed to apply the theoretical part of the description of the buildings, functional rooms and design methods to the graphic part, that is the conceptual floor plan of the family house.