2.  To provide a realistic accurate idea of the cost  Provide information about building or not

3.  Design estimates - screening - preliminary - detailed - engineer  Bid estimates - Contractors´ will to win - Built by the lowest bidder  Control estimates - monitoring project - budget estimates

4.  Plans, sections and other relevant details of the work  Specifications indicating the exact nature and class of materials to be used.  The rates at which the different items of work are carried out

5.  Estimating Materials  Labor Estimating  Estimating Plan  Time Estimating