WHY ESTIMATING IN CONSTRUCTION - Essay Example

Only with such forecasts can clients be informed of the likely financial commitment. Designers need advice on the effect of their decisions on the cost of the project, and contractors need to be confident that the estimates that form the basis of their tenders are realistic. If their tender prices are consistently high they will fail to attract work, alternatively if their prices are too low, they will gain work at unprofitable rates. “Cost estimating methods have followed closely the division between the design phase and the construction phase” (Ogunlana, 19).

During the design phase the cost estimate is the principal responsibility of the client’s cost estimator: the quantity surveyor or the design engineer. The estimate of detailed construction costs is seldom commenced until the tendering process is set in motion, and a contractor is requested to tender for the work. The level of detail included within the cost estimate will be dependent upon the client’s requirements and the stage within the project that the estimate is required. In the design stage the information available and the speed at which estimates are required precludes the preparation of a detailed estimate.

It is not until the period immediately prior to the start of construction that the level of information available enables a detailed estimate to be produced. Where the work is put out to tender it becomes the responsibility of the client, or his representative, to provide sufficient detail of the project to enable a detailed estimate to be prepared. Construction cost estimating may therefore be divided into two categories: design phase cost estimating and contractor’s cost estimating. Within each of these two categories there are several different methods of producing cost estimates.

This paper provides a description of the estimating methods used in the design phase and also describes