Scope creep Project scoping Factor analysis Structural components Substructure Superstructure Finishes Building services Construction management Change control

The aim of this study is to examine the effect of design changes on various elements of building on project cost in Benin City by identifying the common causes of such changes, analyzing how they influence specific building elements including substructure, superstructure, finishes and various services assessing their contribution to cost overruns. 714 target population were identified with 159 responses received. The study identifies client-driven revisions and inadequate project scoping as the chief catalysts for increased costs, necessitating expensive rework, demolition, and administrative overhead. The research specifically analyzes how these design changes impact elemental costs, particularly those affecting major structural components. Through factor analysis, the cost influences are grouped into three main clusters: primary structures framework, enclosed & internal partition, interior finishes & components, and services & Site-Related operations. To counter these issues, the study advocates for mitigation strategies focused on creating a clear and detailed scope of work early on, concluding that establishing a realistic contingency budget and ensuring strong leadership are vital for maintaining financial stability and minimizing the negative effects of design changes. Furthermore, the implementation of a rigorous Change Control Protocol is advised to clearly quantify both direct and indirect costs such as schedule penalties and administrative time associated with every deviation. Finally, the research advocates for strengthening project leadership by empowering Project Managers to exercise abstract reasoning and act as financial stewards. By conducting regular budget adherence meetings and utilizing cost-to-complete forecasts, leaders can better manage client expectations and act as a deterrent to non-essential scope creep, ultimately safeguarding the project's financial stability