The Effective Components in Prefabricated Housing Design : a Systematic Review

On one hand the rapid population growth and increasing demand for housing, and on the other hand the need to reduce the delivery time of construction projects and accelerate capital return, necessitate the transition from traditional construction methods to industrialization. Moving towards industrialization responds to the current demand of the society and it also has a very positive effect on the construction speed, quality and the final cost of the building. It is also capable of increasing the production and establishing a balance between supply and demand. Therefore, by considering the widely expressed advantages of building industrialization and the efforts of governments to take advantage of this, it seems that the effective implementation of this process depends on the identification and application of the effective components in design. Despite manifold empirical studies on these components, the dispersion and lack of a conceptual framework for their classification reveals the necessity of conducting a comprehensive examination in this regard. The purpose of this research is to identify the effective components in the design of prefabricated houses. This paper uses the Sandelowski and Barroso’s Meta-Synthesis to systematic review the sources and analyse all the qualitative data for components identification. By extracting the components and integrating similar cases, a broad classification framework was proposed for categorization of the components into environmental, technical, economic, functional, socio-cultural, aesthetics and climatic groups. Examining the components abundance for internal and external sources has also identified the most frequent ones, which is a guide for designers in prioritizing effective components in the design process. The hierarchies of frequency of groups are almost consistent with each other, and technical, environmental and functional groups have been the most frequent groups among internal and external sources, respectively.In addition to forming an integrated conceptual framework based on the mandatory/recommended hierarchical structure, the number of components and their abundance in each group, this research has applied the use of components and it can be a basis for proposing design improvement strategies in prefabricated housing. An overview to the conceptual framework indicates that: the use of modularity theory for dividing the building components in the technical group, saving energy and materials in the environmental group, providing flexibility in the functional group, saving the Initial costs in the economic group, reducing nuisance for neighbours and passages and considering the market and regional demand for the selection of materials and components in the socio-cultural group, providing appropriate temperature and ventilation in the form of providing environmental comfort in the climatic group and taking advantage of diversity and avoiding monotony in the facade and composition of building components in the group of aesthetics are the most frequent and effective components in the seven groups of prefabricated housing design, and considering them is necessary for design. The reliability and validity of the results were investigated by the use of Cohen's kappa coefficient. In the present study this coefficient is at the significant level of 0.007 equal to 0.750 and this amount confirms the reliability of the research.