4. Inexperienced or unqualified contractors: Hiring contractors who lack experience or qualifications can lead to poor workmanship, construction defects, and delays in completing the project. 5. Change in project scope: Unexpected changes in the project's scope can disrupt the construction process and result in delays and increased costs. 6. External factors: Factors beyond the control of the project team, such as adverse weather conditions, labor strikes, or material shortages, can significantly impact construction timelines and budgets.