The purpose of this study is to analyze and evaluate the Chayama and Sunabe project in Okinawa provided by the Ryukyu Housing and Development Estate (RHD)by looking at the extension process of their extensible houses. As survey methods, observations of housings and interviews with residents were used. Some results show as follows: 1) The extensible style was introduced by RHD to make the best use of RC construction. However, extensible style was not a main factor of purchase for residents. 2) The transisional process is divided by 3 terms, mass renovations at the beginning, extension term, stable term. At the extension, 4 types of extension styles were observed and it is thought that the provision of spatial diversity. The utilization greatly affects the life-style of dwellers especially for reserved space as extension of housing. The extension able space assure the residents that they make the diverse and flexible life which is stemmed from their autonomous life style.