集落における建築代謝の時間構造の変化に関する研究 : 沖縄県与那国島における事例研究

The process of gathering and building materials, maintaining a house and dismantling it, can be called the architectural metabolism. This process has much weight with the household, communal or urban activity. In this study, time of concern is selected as index to survey the relationship between the architectural metabolism and the related communal activity. An islandal society of Yonaguni with 2188 residents which is located in the south-west end of Ryukyu Islands, is selected for the survey area. Time of concern is classified into three categories, domestic, communal and market time, and houses are also classified into three types : thatch roofed wooden house (THWH), tile roofed wooden house (TIWH) and reinforced concrete house (RCH). The data refering to time of concern were gathered in Sonae in 1979. Data sources consisted of hearing survey, census and materials of town office. Hearing data were gathered from home owners of each type houses, craftsmen and the oldest inhabitants. Time of concern spent on building and maintaining each type of houses are shown on the number of participants multiplied by the number of days spent by them. The results of investigation can be summarized as follows. (1) Total time of concern needed throughout lifecycle of a house increases in the order of THWH, TIWH, RCH. If household time needs to get income, a part of which should be spent for materials purchase is added to the time, total household time increases in same order. Time spent by communal labor and by craftsmen becomes maxium in case of TIWH and minimum in RCH. (2) In order to evaluate the historical change of housing metabolism, four models are assumed : (a) all of the houses are THWH's (b) TIWH's. (c) mixture of three types. and (d) RCH's, whereas the population and the number of houses in the island are assumed to be constant. Time directly spent by household decreases in order of (a), (b), (c), (d), but total time spent in household becomes maximum in (d). Time spent by communal labor or claftsmen is maximum in model (b). Total time for participating is maximum in (c), that indicates the present state of the numerical composition of the houses. From these results the proplems which would arise in future are; (1) an increase of load of communal labor because of population, (2) difficulty of building TIWH because of the rising cost of the housing materials, (3) unsuitableness of TIWH, which need much maintenance time, (4) heavy load of cost of building RCH. Some proposals which are made in conclusion are on the requirements of planning houses in near future to improve the problems of the time structure.