Scan-to-BIM technique in building maintenance projects: practicing quantity take-off

PurposeIn Hong Kong, over 20,000 private residential buildings will be 50 plus years old by 2039. However, building maintenance has not been owners’ popular interest because of the high cost as well as the complexities in justifying whether the quantities and prices of the maintenance works are reasonable. This paper therefore aims to validate the practicality of adopting Scan-to-BIM: Terrestrial Laser Scan (TLS) and Building Information Modelling (BIM) to perform quantity take-offs (QTO) for estimating building maintenance costs.Design/methodology/approachA 64-year-old tenement building was selected to conduct a case study. In this instance, the building had undergone a Scan-to-BIM survey approach to generate QTO for the bills of quantities for external painting works. The Scan-to-BIM approach includes site visit, positioning of scanning equipment, assignment of circular scan routes, point cloud registration and identification of residual error. After that, time, cost and quality data were logged into contrast with QTO on as-built plans for external wall plastering works.FindingsThe “time”, “cost” and “quality” of the Scan-to BIM practice were then examined and compared with the prevailing practices of manual measurements on as-built drawings. As noted from the results, the initial cost of Scan-to BIM is high, owing to the cost of equipment, software and capable available operators. However, the authors identified that the time and cost can be significantly minimised by developing and implementing efficient practices such as preparing a detailed scan plan, equipping modeller with quantity surveying knowledge, using automated object recognition and 5D BIM software packages such as Vico Office and CostX.Practical implicationsThe upshot is that Scan-to-BIM could be one of the measures to advance the clarity in the QTO and estimated price of the maintenance projects.Originality/valueThe practicability of Scan-to-BIM has received limited attention on existing building maintenance project. The Scan-to-BIM approach was examined using a case building of a 64-year-old tenement building. The approach demonstrated in this research study is promised to advance the clarity in the QTO and estimated price of maintenance project.