__Estimation and costing__**Importance of estimation:**

The following are importance of estimation to get the data of funds to be sanctioned by the owner or authority. the estimation is very important.

If proper estimation is done , then an engineer will be done to optimized the use of sanctioned fund.

In estimation, quantities and grade of materials are mentioned, so an engineer can do the use of materials efficiently.

If an owner or authority want any loan from banks, then for demanding loan, estimation is required.

Any construction will be a time bound program with condition of available funds.

**Different type of estimates:**

the following are the different type of estimate;

- Approximate or abstract estimate or rough cost estimate.
- Plinth area estimate
- Cube rate estimate or cubical content estimate
- Approximate quantity method estimate
- Detailed estimate or item rate estimate
- Revised estimate
- Supplementary estimate
- Supplementary & revised estimate
- Annual repair estimate

**Approximate or abstract estimate or rough cost estimate**

This is require for study in basic way of work or project to decides the financial posiyion and policy for admintrative sanction by competent administrative authority.this type of estimate is prepared for the practical knowledge and cost of similar works.the estimate is accompanied by a brief report explaining the necessity of the project.

**Plinth area estimate for building**:

This is prepared on the basis of plinth area of building the rate being deduced from the cost of similar building having similar specification,height and construction in the locality.

Plinth area estimate is calculated by finding the plinth area of building and multiplying by the plinth area rate.

**Cube rate estimate or cubical content estimate**

This is calculated by finding the cubical content of the building and multiplying by cubical rate.

**Approximate quantity method estimate:**

In this method approximate total length of wall is found in running meter(RM) and this toatal length multiplied by the rate per running meter of wall gives a faisly accurate cost.

**Detailed estimate or item rate estimate:**

Detailed estimate is an accurate estimate and consist of working out the quantities of each item of work and working the cost .the dimension (length,breadth & height).

**Revised estimate**

Revised estimate is a required to be prepared under any one of the following circumstances:

- When the original sanctioned estimate is exceed or likely to exceed by more than 5 %.
- When the expenditure on a work exceeds or likely to exceed the amount of administrative sanction by more than 10%.
- When the expenditure on a work exceed or likely to exceed the amount of administrative sanction by more than 10%.
- When there are material derivation from the original proposal ,ever though the cost may be met from the sanctioned amount.

**Supplementary estimate**

This estimate is a detailed estimate and is prepared when additional works are required to supplement the original works or when further development is required during the programs of works.

**Supplementary & revised estimate:**

When work is partially abandoned and the estimate cost of the remaining work is less than 95 % of the original work i.e. less than 95% of the original sanctioned estimate or when there are material deviation and changes in the design which may cause substainal saving in the estimate, then the amount of original estimate is revised by the authority.

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