# Construction Estimation in Civil Engineering

The civil engineering project planning and their implementation will ask for estimation for quantities and costs in order to meet the objective of the project.  The cost of the project is estimated by the construction project manager.

## What is Construction Estimate or Project Estimate??

 Fig.1. Different Bodies involved in Estimate Preparation The preparation of Detailed estimate will require the following elements: 1. The Quantities of the Items involved 2. The cost of the items involved Quantity Estimate: The quantity estimate is called the method of obtaining the quantities of the items involved in the project. Rate Analysis: The method of obtaining the unit cost of items involved in the project is called as Rate Analysis.
Construction Estimate can be defined as the process of calculating the quantities and the costs of various items involved in the constructed project. The preparation of estimate is carried out by initially obtaining the quantities of items that are required to complete the project and then multiplying by their unit price. The purpose of carrying out the estimation process will decide the details required for an estimate.

Note: The Estimation carried out in preliminary stage must be accurate enough to produce the cost of project within 10 to 15% variations
Different parties will ask for different forms of estimates, throughout the course of the project. The details and the method of estimation are dependent on the needs and the levels of the decisions of the management.

## Example of Estimating the Project

Consider a plan for constructing an academic institute. The organization needs to know how much money has to be spent for the same. This can be estimated from the cost of a similar project constructed previously.

Say if, per student, the amount of money invested is Rs.20,000. Then if the academic institute is planned for 10,000 students, the amount required will be 10,000 x 20,000 rupees.

The next stage of details that is necessary is the investment cost for subheads, equipment, laboratories, hostels etc.  This is determined by knowing the area of construction and the cost of construction per unit area. If the construction of a hostel facility has to be done based on the drawing and specification, then the estimate is prepared based on the drawings and the specifications given as per the given rules. This estimation is the basis on which the contract is evaluated by the client.

The contractor while bidding on the hostel project, he will prepare an estimation such that he can but the contract and get profit from the execution of the project. During the construction period, the company has to prepare an estimate for the order and the supply of the material and also carry out the resource planning.

This example shows that the estimate for the same item will differ based on the details that are required for the project implementation. The purpose of the estimate will decide the accuracy of the estimate. For example, the estimate of material supply is very necessary to make the storage of material accurate thus avoiding burden for the project.

Different Levels in the Preparation of the Estimate

Preparation of  estimate will have different bodies involved:

1. The client or the owner or the staff of the owner (Project Manager)
2. Contractor's Personnel
3. Material Supplier and Contractor

Challenges in Estimation of Construction Projects

 Fig.2.Challenges in Estimation of Construction Projects

Different challenges faced in estimation works carried in the project is more concerned with the personnel who carries out the estimation i.e the estimator.

The background work for estimation in the organization is carried out by the higher management who keep the records of the cost of unit items called as the schedule of rate, schedule of productivity and guideline for the basic calculation. Junior level or the assistant engineers will carry out the basic calculation.

The estimator not only wishes to calculate the quantity of the materials and the cost but also to coordinate with different parties whoever is involved in the project. In order to obtain different details of the cost and explanation for higher management, it is necessary for the estimator to get involved with the site engineer, instrument manager, senior management staff, materials supplier etc.

The estimator has to understand the project details, specification, drawings, working conditions, equipment, and labor and also the collection of other data from the site.

The estimator has to assess the details of the temporary works like formwork for concreting, temporary plant for the storage of the materials. This means the estimator bring the correct guess of what the project is on a paper.