The most effective means of production organization in a housing project is the flow-line method. (1) The construction process is highly repetitive, the underlying principle closely resembles that of industrial mass-production the process is resolved into balanced production lines operated by specialized gangs at a uniform pace, and the project is broken down into sections (e.g. a story or part of a story) dealt with by one gang at a time in a predetermined sequence. This approach permits an optimal reduction of cost and construction time. Reduced construction time is at present one of the main concerns of the building industry in many countries. Although the main contribution has to come from the contractor (through improved planning and organization), decisions by the designer or the client during the planning stage of the project also have a direct bearing. Hence, the obvious need for better understanding by all participants in the project of the factors affecting construction time. This is especially important in this industry, where the production process is divided among several contributors joining at different stages of progress.