Cost Estimation in Construction BIM vs Total BIM Master’s thesis in Design and Construction Project Management

Abstract

It is known that cost overruns are an issue in the construction industry, and in an industry with such small margins of profit there is always a desire to cut costs. To facilitate and improve the efficiency and quality of cost-estimation processes, the implementation of Building Information Modelling (BIM) has been promoted in the construction industry. Recently, the concept of ‘Total BIM’ has emerged in Scandinavia, where the BIM becomes the legally binding construction document. This approach excludes traditional 2D-drawings and puts more requirements on the actual BIM, which should then promote more use within cost-estimation. This thesis highlights, explores issues, challenges, and potential within the cost-estimation process. 10 interviews were conducted with participants from recent projects involving the use of BIM and traditional construction documents in parallel. Secondly, an in-depth investigation of a Total BIM project was performed with respect to model quality, quantity take-offs, and cost estimations. Findings show that even in projects where BIM is present, traditional 2D-based methods were still used for cost-estimation. Common reasons include lack of trust for the BIM, the BIMs unclear legal status and quality, and that the existence of traditional 2D-drawings makes it possible to still use “tried and tested” methods. By using Total BIM, the time taken to perform cost estimations may be reduced up to 90% over traditional methods, but issues regarding training, data and information management and education must be addressed. Greater investment is also necessary in early project stages.