ESTIMATION

ESTIMATION IS DEFINED AS THE PROCESS OF CALCULATING THE QUANTITIES AND COSTS OF THE VARIOUS ITEMS REQUIRED, IN CONNECTION TO A CERTAIN WORK SO AS TO SUCCESSFULLY COMPLETE THE WORK.

WHY IS ESTIMATION CARRIED OUT?

1. TO KNOW THE QUANTITY OF MATERIALS REQUIRED

2. TO FIND OUT THE APPROXIMATE COST OF A PARTICULAR WORK.

3. TO KNOW THE VALUATION OF PROPERTY.

4. FOR THE PURPOSE OF ADMINISTRATIVE APPROVAL & TECHNICAL SANCTION.

5. FOR INVITING TENDERS.

TYPES OF ESTIMATES

THERE ARE TWO TYPES OF ESTIMATES -

1. DETAILED ESTIMATE - 

• IT IS PREPARED BY  CALCULATING THE ORIGINAL QUANTITIES OF VARIOUS ITEMS OF WORK & LATER MULTIPLYING THE CALCULATED QUANTITIES BY THEIR CORRESPONDING RATES.
• THE QUANTITIES OF VARIOUS ITEMS OF WORK ARE CALCULATED USING THEIR DIMENSIONS FROM THE DRAWINGS.
• DETAILED ESTIMATE IS PREPARED WITH THE HELP OF MEASUREMENT SHEET & ABSTRACT SHEET.

DETAILED ESTIMATES ARE FURTHER CLASSIFIED AS -

• SUPPLEMENTARY ESTIMATE
• REVISED ESTIMATE
• MAINTENANCE & REPAIR ESTIMATE
• REVISED & SUPPLEMENTARY ESTIMATE

USE OF DETAILED ESTIMATE -

• IT IS REQUIRED FOR  ADMINISTRATIVE APPROVAL & TECHNICAL SANCTION.
• TO FIND OUT THE ACCURATE COST OF PROJECT
• TO KNOW THE MATERIALS & LABOURS REQUIRED
• TO FRAME & INVITE TENDERS ETC.

2. PRELIMINARY ESTIMATE or APPROXIMATE ESTIMATE - 

• IT MAY BE DEFINED AS A ROUGH ESTIMATE PREPARED TO KNOW THE TENTATIVE COST OF WORK  IN LESS TIME.
• IT IS USEFUL TO KNOW  THE COST & FEASIBILITY OF PROJECT AT EARLY STAGES.
• IT REQUIRES LESS SKILL AND TIME AS ONE CAN PREPARE APPROXIMATE ESTIMATE, WITH REFERENCE TO THE ACTUAL COST OF SIMILAR EXISTING STRUCTURE.
• VARIOUS FACTORS OF COMPARISON INCLUDE PER CAPITA , PER KM , SERVICE UNIT , CUBIC CONTENT ETC.

METHODS FOR CARRYING OUT APPROXIMATE  ESTIMATE INCLUDE -

• CUBIC CONTENT  METHOD
• PLINTH AREA METHOD
• SERVICE UNIT METHOD
• TYPICAL BAY METHOD
• APPROXIMATE QUANTITIES METHOD

USE OF PRELIMINARY or APPROXIMATE ESTIMATE -

• TO KNOW THE INVESTMENT REQUIRED.
• TO KNOW THE BENEFIT COST RATIO i.e FEASIBILITY OF THE PROJECT
• TO PLAN THE PROJECT.
• FOR BANK PURPOSES (LOAN, INSURANCE ETC.)