The post-disaster housing practices in Turkey are to be evaluated in two different phases, as before and after earthquakes in 1999, due to improvements in housing quality. Consideration of permanent houses with their surroundings and delivery of houses to the user for the first time with appliances such as kitchen cabinets and wardrobes are some of these major improvements. However, there is a still basic problem about post disaster houses. This problem is inflexibility which is related to the architectural and structural characteristics of the house that is not compatible with the users’ needs and cannot be converted into a compatible condition. Inflexibility which causes inadaptability between the user and house negatively affects physical, social, cultural and economical sustainability of locations. The aim of this paper is to question housing construction in Turkey in terms of inflexibility problem and to emphasize that flexibility is a concept which is to be considered in the entire structure of housing, which comprises architectural concept, structural components and production period. The study on this paper manifests user preferences regarding flexibility and the factors influential upon such preferences. For this purpose, a research was carried out on two different types of permanent houses in centre of Düzce province and Gölyaka district. 89 persons were subject to an interview during the research. Four plans were derived from both types of permanent houses in order to identify users’ preferences about flexibility in architectural terms. Three of these plans are partially flexible, and only one of them provide total space flexibility. Users’ approaches towards structural flexibility were assessed upon their preferences in respect of four different construction systems, consisting of timber, masonry, steel and reinforced concrete. Architectural and structural options offered to the user were illustrated via a three-dimensional drawing program. The research revealed that the user preferred specified, guiding and partially flexible types of plans, rather than a wider and indefinable flexibility option. On the other hand, the user preference of systems and even materials different from reinforced concrete is evaluated as a significant result in terms of structural flexibility. This result is regarded as an indicator of the fact that differences to be created in material and system for ensuring flexibility of house might be adopted by the user. ‘Steel construction system’ is preferred rather than concrete in Gölyaka, while ‘timber system’ is preferred in Düzce. The research also reveals the factors having an impact on user preferences. These include user approaches observed during selection process, their demographic structures, assessments about house sizes, primary needs in terms of house, and previous housing experiences. It was observed that the user was not confident about their preferences on the issue of how and to what extent they could arrange the house. Therefore, they preferred ready-made plans which included identified and guiding flexibilities. Furthermore, the type of plan mostly preferred in both districts contains the solution of problem regarded as the primary need in terms of housing. The houses in Gölyaka, which are extremely small with one bathroom, do not meet the needs of crowded families forming the major part of population in the district. Whereas, a bath plan consisting of three sections, all of which are available for use, is used both in conventional and modern general housing type of the district. Thus, another plan with a second toilet section were preferred in Gölyaka. However, the houses in Düzce have more space with an extra room a second toilet; moreover, the average number of users per house is smaller. Nevertheless, the housing sections are small due to intense social relationships in the district, which stand out as an important problem. The users preferred the type of plan which integrates the third room with the kitchen when required, aiming to create a wider living space. Another important result is that total space flexibility is preferred more in Düzce compared to Gölyaka, basing on the view that the area of use in the house is found sufficient. Here it is seen that insufficiency in size of house is an important barrier before house flexibility. In conclusion, the concept of flexibility which will provide user participation should be considered in the entire of house. Type and degree of flexibility should be identified by taking into account social & cultural structure and expectations of users. Flexibility concept should be made preferential target of post-disaster housing policy in our country, in terms of living spaces in conformity with user values; physical, social, cultural, economic sustainability of living spaces.