"Tower House" is a three-dimensional one-room house that expands vertically by laminating floors without partitioning by fittings and partition walls, showing one way of urban housing. A house called "Skip-floor type" is a house in which floors with different levels are connected three-dimensionally, creating open interior space. Compared to houses with rooms as the main unit, houses with "floors" as the main unit are characterized by open and cohesive interior space, and this study refers to these houses as "open laminated houses". Open laminated house is often found in narrow sites due to the subdivision of site in recent years, and various design can be seen depending on sizes, connections on the flow line, level differences, etc. with the "floor" forming each layer as a composition unit. The "floor" is an element that can create integral unity or ambiguous and ambiguous unity inside the room. Therefore, in open laminated house whose main composition unit is the "floor", it is considered that the operation of partially segmenting by the "floor" and the operation of integrating the parts are occurring at the same time. It seems that a precise composition method can be extracted.
In this research, we focused on the "floor", which is a composition material of the internal space, for 75 open laminated houses built in narrow site, and analyzed the space by analyzing the size, level difference, and floor group due to the level difference. The purpose is to clarify the characteristics of the composition and obtain effective knowledge about the design method of houses built in narrow site.
Initially, we analyzed the size of the floor from the floor area ratio of the open laminated house, grasped whether or not it has a "main floor". Secondly, from the combination of level differences, we grasped whether or not there is a "floor group" and its positional relationship by dividing it into the ground floor and the upstairs. Finally, by integrating these, we clarified the composition of open laminated house built in narrow site. The results are as follows:
1) In a composition with both a main floor and a floor group, we found the composition operations of "fusion" and "dispersion" of the main floor and floor group, and "coexistence" of fusion and dispersion.
2) In a composition with either a main floor or a floor group, the characteristic of small house was that it secured a main place on the upstairs.
3) In a composition that does not have either the main floor or the floor group, there was a characteristic that emphasized the laminating method itself.
There is also a composition that provides a strong centripetal place in narrow site, but the feature by size and the unity of the floor are divided into upper and lower parts and dispersed, so that there is no strong center somewhere and the entire interior space is expanded. In recent years, there has been a tendency to create a composition that does not have a center and creates an expanse in the entire interior space by laminating multiple floors, and a new characteristic of the space composition of open laminated house has been clarified.
