The plinth area estimate is not considered in Courtyard area.

Estimating may be defined as the forecast of the probable cost of the building or a project prior to the commencement of the job.

The different types of estimates are

(i) Detailed estimate or Item Rate estimate or Intensive estimate.

(ii) Plinth area estimate

(iii) Cubicle content estimate or the cube rate estimate.

(iv) Revised estimate.

(v) Supplementary estimate

Plinth area estimate:- In the plinth area estimate the plinth area rate is arrived at by dividing the cost of existing structures with similar specifications and construction in that locality by the plinth area. Now the estimated cost of the proposed structure is calculated by multiplying the plinth area of the structure with the plinth area rate.

Thus for example, if the plinth area rate is Rs. 1500 per sq.m, the plinth area estimate of a building with a plinth area of 100 sq.m will be Rs. 1,50,000. The plinth area is computed as the covered area by taking the external dimensions at the floor level. Courtyards and other open areas are excluded.

In cases where the plan of the building is not ready or available, and the plinth area cannot be accurately determined, the estimate may be made by estimating the proposed floor area of the rooms from the functional requirements, and about 30 percent to 40 percent of this total added to account for walls, circulation area, etc., and an approximate cost may be obtained by multiplying the unit rate and the estimated plinth area rate.