Building contractors are independent construction specialists who bid on specific assignments within major construction projects. The construction of one large building might involve many contractors and subcontractors working together towards its completion. A building contractor finds, solicits bids from and schedules all of the subcontractors that are necessary to complete the project. A contractor first analyses the work specifications, determines the materials, personnel and related costs required to complete the assigned task and then submits a quotation. If the tender is accepted, the contractor purchases materials and works according to the job specifications and makes use of various skilled artisans and labourers who are assigned to the project. An apprenticeship is a 4-year contract between company and apprentice, comprising a 12-week theoretical training, which includes 4 subjects at national exam level.