Understanding the effect of non-value-adding activities on construction project cost: main effects and causal relations

In the construction sector, cost overruns are still an ongoing issue, especially in developing nations like Malaysia. Physical waste receives a lot of attention, but process-related inefficiencies, particularly Non-Value Adding Activities (NVAAs), have a significant but sometimes disregarded effect on project costs. This study focused on the eight categories of NVAAs: overproduction, waiting time, non-utilized talent, inventory, motion, transportation, and additional processing. This study determines the extent to which NVAAs effect construction costs and the root causes of these inefficiencies. A mixed-methods strategy was used in this study, which included questionnaire surveys, semi-structured interviews, and diagramming. According to the study, the most important NVAAs causing construction cost overruns are defects and waiting times. Industry stakeholders rated defects as having the highest severity. Moreover, it has been discovered that low tender price methods, poor planning, and bad procurement practices are frequently the causes of these significant NVAAs. The results emphasize how urgently improved planning, awareness, and stakeholder collaboration are needed to improve cost performance through the removal of NVAAs from building processes.