What Is the Estimate?
Estimation is the process of calculating item s for different techniques required for any task. The estimate gives an estimate of the total cost.
Making estimates is becoming more complex day by day due to various factors, and estimating has been simplified by modern techniques in modern times.
Estimation is a technique of estimating different amounts of work in which the total expected cost of a particular work or project is used.
The estimate is usually prepared before the project starts. They are prepared in different types depending on the various requirements of the project.
Requirement Data for Estimate
Before starting work, various data related to that work is important, Which are as follows.
1. Drawing ( plans ,sections ,etc)
The plan should have the required sectional elevation and various accurate scale drawings with full dimensions. Generally, layout plans, different section elevations, and sectional elevations are drawn on a scale of 1 cm = 1 m.
For the preparation of estimates, the cost of various works is requested. Prices of various items used in construction and salaries of different labor groups like skill and unskilled labor, carpenter, fitter, etc., are considered.
It is important to know the distance from the cost of transportation of the job location and the source of materials.
These values can be obtained from the government PWD schedule of the rate book, or the rate can be found using the “rate analysis” method.
There are two types of specifications
The general specification indicates how to work according to the design of the work and materials used in the different sections of the work.
General Requirements Helps shape the various concepts of the constitution as per the whole building drawing and show the details.
It gives a detailed explanation of the various works that demonstrate the work to maintain the quantity and consistency of the components.
Type of Estimate
The types of the estimate are as follows
- Initial cost Estimate
- Cube Rate Cost Estimate
- Plinth Area Cost Estimate
- Approximate Quantity Method Cost Estimate
- Detailed Cost Estimate
- Revised Cost Estimate
- Supplementary Cost Estimate
- Annual Repair Cost Estimate
1. Initial Cost Estimate
Initial cost estimates are also called budget estimates. The engineer usually prepares these estimates at an early stage to know the project’s estimated cost. With this estimate, the financial condition, policy, and rules for the administration department having competent approval authority can be determined.
Preliminary estimates are usually prepared in terms of the cost of similar projects. In this estimate, the estimated value of each important item of the work is shown individually, knowing the need and usefulness of each item of the work. Various work items include the cost of land, roads, electrification, cost of water supply, cost of each house, etc.
2. Cube Rate Cost Estimate
The cube rate value of a building is estimated by multiplying the building’s height, the plinth area, and the cube rate.
In this type of estimate, the height is calculated from the plinth floor level to the terrace floor level. It does not include parapet.
3. Plinth Area Cost Estimate
In this estimate, first, the plinth area of the building is found. Then the cost estimate can be obtained by multiplying the plinth area and the plinth area rate.
Open areas of the building, courtyards, etc., are not included in the plinth area. But if the building is multi-story, the floor area is estimated for each floor level.
Suppose the plinth area of a building is 150 m૨. And its plinth area rate is 2000 per m૨. So its plinth area cost estimate is 150 * 2000 = 300000 rs.
4. Approximate Quantity Method Cost Estimate
In this method, the total length of the building’s wall is measured then the total length of this wall is calculated with rate.
The value of this calculation is the value of the building. In this method, the rate per running meter is calculated separately for foundation and superstructure.
This method is kept separately for cubic items for a foundation like excavation and brickwork. When works being done in superstructures like furniture work, brickwork for walls, electrician work, flooring work, etc. The rate per running meter is fixed.
5. Detailed Cost Estimate
They are primarily designed for the following two purposes
1. Execution processes
2. Obtaining technical sanction
A detailed estimate of the cost is prepared after the competent administrative officer has approved the initial estimates. This estimate is detailed and accurate. The quantity of each item of work under a project is measured, and the value of each item of work is calculated.
Rates for different items are provided according to market rates, and the total estimated cost is calculated. Some% has been added for the estimated cost in case of contingency.
Establishment costs for monitoring are also mentioned in the detailed cost estimate.
This estimate includes the estimated amount for the service charges, including water supply connection, sanitary arrangement, and electrical installation.
The detailed estimates include the following, which is as follows
- General specifications,
- General Report
- Drawings / Plans – Layout plans,
- Sectional views
- Detailed drawings etc.
- Basic rate adopted in rate analysis etc.
6. Revised Cost Estimate
A revised cost estimate is a detailed estimate and is prepared when the value of the original approved estimate increases by 5%.
This type of item may increase due to a sudden increase in transportation cost etc. The reason behind the revision of the estimate is mentioned on the last page of the revised Estimate.
A supplementary cost estimate is a detailed estimate and is prepared when the original work is in progress, and additional work is required. The budget should include the cost of the original estimate and the total cost of additional work for which approval is required.
8. Annual Repair Cost Estimate
The annual repair cost estimate is also called the annual maintenance estimate, which is prepared to know the maintenance cost of the building during the year, which will keep the structure in a safe condition. Whitewashing, painting, minor repairs, etc., are taken into consideration while preparing the estimate of the annual repair of the house.
Advantage of Estimate
- Estimate gives the estimated duration of the work.
- The estimated cost of the work can be known from the estimate.
- More accurate estimates simplify the project. Unexpected costs and blocked working capital can therefore be avoided.
- Properly guessed work is flawless, and projects are completed quickly.
- Various things related to that work can be made available.
- Staff can be counted from estimates such as supervisor, engineer, senior engineer, etc.
- Work planning can be made easier with estimates.
- The estimate is made keeping in view the previous years so the mistakes made in the previous years can be removed.
- Materials can be ordered as required
Disadvantage of Estimate
- The estimate cannot communicate between labor and supervisor.
- Changing the method of estimation does not maintain the quality of the material.
- Good efficiency cannot be achieved with every task.
- Certain types of overhead costs cannot be controlled.