ABSTRACT
The study carefully examined the cost implications of variation on total contract cost of building projects. It also investigated the extent to which the variations affect the initial contract sums of such building projects. The study which is mainly based on project files and interaction with professionals and clients draws samples of twenty-three (23) completed projects from four states (Kaduna, Kano, Anambra and Imo) within the area of interest. The initial contract sums were obtained from the bills of quantities while the final contract sums were obtained from the final accounts. The sums were subsequently broken down into group building elements. This work shows that the overall increase over initial contract sums is 22.7%. The various final account statements attributed these increases to substructure 3.0%, superstructure 5.7%, finishes and Services has each 3.7%, lulling and furnishings 0.96%, External works 2.1% and preliminaries 1.3%. The gravity of the problem is different for the two types of clients studied, that is, public client 39.1%. and private client 7.2%. The study concludes that variation in most cases result in cosl and lime overruns. Also, since substructure, superstructure, finishes and services have the highest cost magnitude in relation to the total contract sum, they could be seen to be the most critical elements requiring the greatest attention during construction. Suggestion for reducing variation in construction projects includes, adequate planning, comprehensive pre-contract planning , adequate design briefs, guided by proper feasibility and viability studies should be embarked upon before commencing any project. Also Architects should ensure that Quantity surveyors are allowed to estimate the variations before issuing variation orders