Assessment of Cost Overrun Causes in Public Housing Projects: A Case Study of Abuja Municipal Area Council

Cost overrun remains one of the most persistent challenges confronting public housing delivery in Nigeria, with significant consequences for budget planning, project completion timelines, and stakeholder trust. This study investigates the primary causes of cost overruns in public housing projects within the Abuja Municipal Area Council (AMAC), focusing on projects executed between 2019 and 2024. Using a descriptive survey design, data were collected from quantity surveyors, project managers, and contractors involved in identified housing schemes through structured questionnaires. A total of 85 respondents participated, and data were analysed using relative importance index and frequency distribution tables. Findings indicate that inaccurate initial cost estimates, fluctuation in material prices, scope changes, and weak contract administration are the dominant causes of cost overruns in the study area. The research also reveals that poor pre-contract planning significantly amplifies cost escalation during project execution. The study recommends that government agencies adopt robust pre-contract estimating procedures, engage qualified quantity surveyors at project inception, and implement strict change management protocols to curb unnecessary scope additions. Additionally, the use of price adjustment clauses in contracts is advised to manage inflationary risks. This study contributes to the growing body of knowledge on construction cost management in Nigeria's FCT and provides practical recommendations for improving public sector housing delivery. Keywords: cost overrun, public housing, Abuja, quantity surveying, contract administration