Building construction is a process that includes several interrelated activities. The basic goals of the construction company are to complete a project at the lowest cost and in the shortest possible time. Therefore it is important to prepare and predict all the costs and labor time, and execute controls and actions during construction. This graduation thesis describes the construction of a barn in detail and all the contract documents. It analyzes the deviation of cost and time in building a barn, on basis of a comparison between the contract pre-assessment of costs and the actual cost to the contractor, and comparison between the contract schedule and the actual progress of the work. The tables in the graduation thesis present detailed cost deviations. A description of the reasons for the delays and cost deviations is also included in the graduation thesis.