On-site construction versus prefabrication

Abstract

The question this thesis tries to answer is "How does one decide whether or not to use prefabrication in a project?" Since this is a broad question, we focus on a more specific topic: "How does one decide whether or not to use prefabricated bathrooms in a project?" The problem is approached with the formation of one case study and with the help of construction industry experts (owners, contractors, architects and academics). The case study is created based on data from a real project. The decision-making methodology used to run our comparison is called "Choosing by Advantages" and is described in detail in the thesis. Three alternatives are investigated: on-site bathroom construction, prefabrication of bathrooms adjacent to the worksite and prefabrication in a factory. Experts from the construction industry evaluate the solutions available, given the same information and data, in an attempt to understand which of the options they would consider to be more appropriate. They assign weights on each of the advantages in order to decide which solution is preferable. The primary goal of this thesis is to establish a methodology that can be used to tackle broader problems of the construction industry. Our case study could be used as guidance in addressing wider problems and could help the decision-making process. At the same time, the methodology established can be used to identify where differences in opinions lie, to help project stakeholders focus on these differences and to facilitate them in reaching agreement. A secondary goal for this thesis is to explore the difference in philosophy (if any) between all professionals involved in construction projects. We intend to investigate, for example, if all contractors agree among each other when presented identical information. The results are displayed in chapter 4.