Define Estimate | Types of Estimate

Estimate

Define

It is a method of calculation of various quantities of various items of work that is required to be executed for completion of any work and finding out cost of each item before execution of work.

Types of estimates

Approximate/Preliminary estimate/Rough estimate

1. Plinth area method

2. Cubic content method

3. Service unit method

4. Typical bay method

5. Approximate estimate

Plinth area method

Plinth area of is calculated by multiplying plinth area of a proposed building by plinth area rate of similar existing building having similar specifications in same locality.

Formula: - Approximate cost of building = Plinth area X Plinth area rate

Cubic content method

In cubic content method, plinth area is calculated which is multiplied by height of floor to obtain cubic content of proposed building.

Formula: - Approximate cost of building = The volume of proposed building X Cost of similar building

Service unit method

Service unit of a building is calculated by considering unit of a building in a unit which serves the specific purpose.

Formula: - Approximate cost of building = No. of service unit X Cost of service unit

Typical bay method

Bays are the components or a similar portion of a structure such as space between center to center of consecutive column.

Formula: - Approximate cost of building = Number of bays X Cost of one bay

Approximate estimate

The cost per unit quantity of each subhead is worked out carefully and separately. The quantities under each subhead are multiplied with their respective cost to obtain the approximate estimate of building.

[B] Detailed Estimate

1. long-wall & short-wall method

2. Center - line method

3. Crossing Method

Long-Wall & Short-Wall Method

In this method, the wall along the length of room is considered to be a long wall, while wall perpendicular to long wall is said to be a short wall

Center line method

This method is suitable for walls of similar cross section. Here the total center line length is multiplied by breadth and depth of respective item to get total quantity at a time

Crossing Method

This method is adopted when external wall is of one thickness and internal wall having different thickness. In such cases, center line method is applied to external walls and long wall – short wall method is used for internal walls.