Resumen
The Australian house building industry has been facing an increase in the average house completion time in the last decade. This increase in some states is quite dramatic. For instance, Western Australia has faced a 70 percent increase in the average house completion time during this period. This paper uses two planning approaches to explain this; i) the activity-based planning methods and ii) the workflow-based planning methods. In addition, this research investigates the strengths and weaknesses of these two planning approaches in explaining the behaviour of the house building industry. For this purpose, a national case study and five state case studies including Victoria, Western Australia, New South Wales, Queensland and South Australia have been used. The data related to the key parameters have been collected and their correlation with the average house completion time has been investigated. These key parameters include the average house floor area, the number of house completions and the number of houses under construction. The reasons for the increasing trend of the average house completion time have been postulated in all case studies. According to this research, the increase in the average house completion time cannot be explained using activity-based planning methods. In contrast, by using workflow-based planning methods, it has been shown that the average house completion time is correlated with the number of houses under construction. This paper shows that the average completion time is influenced directly by the workflow in the house building industry and that workflow planning should be the basis for the house building industry planning.