Different body involved in preparation of estimate can be grouped into following three classes.
- The owner or owner's staff such as project manager.
- Contractor's personnel such as senior manager, planner, site management staffs etc.
- Materials suppliers and contractors
The owner generally employs a project manager/engineer, who helps him in preparation of contract documents. The contract documents require the bill of quantities. Also, owner should be aware of the cost to sell the contract. Thus an estimate is required of various quantities. The owner's project manager prepares these estimates. Tender for the contract in a construction company is prepared by higher management. These management are helped by estimators, site engineers and material supplier to prepare the estimate of the job.
Challenges in Estimating
The job of an estimator is not only to calculate the quantity and cost of the material, but to co-ordinate different parties involved in the project or construction in particular. An estimator of the construction company has to get involved with the site engineer, material supplier, instrument (plant) manager and senior management staff to obtain the various details of the cost and explaining the calculation to higher management. An estimator has to understand the project details, study drawing and specification, obtain working conditions, labour and equipment productivity and collecting other data from the site. An estimate also assesses the temporary work at the site such as formwork for concreting, temporary plant for the storage of materials. Virtually, an estimator has to build the project on paper to obtain the right guess.