Estimate in construction is the computation or calculation of the quantities required and expenditure likely to be incurred in the construction of the work.
The estimated cost is not the actual cost. It is the probable cost of the work. It is determined theoretically by mathematical calculations with the help of plans, drawings and current rates. An approximate estimate is prepared by various methods but the accurate estimate is prepared by detailed estimate method.
Purpose of estimate in construction
Main purposes of estimate in construction are:
i. To ascertain the required amount of money to finish the proposed work.
ii. To ascertain the quantities of materials needed to program their timely procurement.
iii. To calculate the number of different categories of workers that are to be employed to complete the work within the scheduled time.
iv. To evaluate the necessity of tools and equipment needed to finish the work according to the program.
v. To fix up the completion time from the volume of works concerned within the estimate.
vi. To draw up a construction schedule and also to arrange the funds needed according to the programming.
vii. To prove the investment from benefit-cost ratio.
viii. To invite tenders and prepare bills for payment.
ix. An estimate for an existing property is needed for valuation.
Importance of estimate in construction
i. It helps in working out the approximate cost of the work.
ii. It is useful to ascertain the work done by the contractor during and after the execution of the work.
iii. Payment to the contractor is done according to the actual measurement.
iv. It gives an idea for the requirement of controlled materials like brick, cement and steel etc.
v. By framing a complete estimate, the client can be advised on
a. Valuation of properties
b. Fixation of the standard rate.
c. The sale price of flats in case the building is constructed on an ownership basis.
d. For claiming the amount of building in arbitration preceding.
Data required for the preparation of estimate
1. Drawing: Fully dimensioned drawings ( like a plan, section, elevation and related other details) are required.
2. Specification: The nature, quality and sophistication of work, materials to be used in the various parts of work, quality of materials, and method of preparation and description of the execution of work provides the detailed specification regarding the project.
3. Rate: The rate of various items of work, materials to be used in the construction and the wages of different categories of labour should be available for preparing an estimate. The cost of transportation should also be known. The rate may be worked out by the rate analysis. After collecting the above information’s; the estimate is worked out.
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