QUANTITY SURVEY AND AND TYPES OF ESTIMATE

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Quantity Survey:

Quantity survey is a schedule of quantities of all the items of work in a building

Data Required for the Preparation of an Estimate or Quantity Survey:

Drawings:

Complete and fully dimensioned drawings (i.e. plans, elevations, sections and other details) of the

building or work in question are required.

Specifications:

Detailed specifications, giving the nature, quality and class of work, materials to be used, quality of

the material, their proportions, and method of preparation are required.

Rates:

The rates of various of work, materials to be used in the construction, wages of different categories of labor (skilled or unskilled) and cost of transportation charges should be available for preparing an

estimate of work cost.

Actual Finished Work:

Quantities can be calculated from the actual work done in the project site.

- The quantities mainly can be calculated as:

Quantity = Length × Width × (Height or Thickness),
Quantity = Area of cross-section × Length,
Quantity = Length × Width,
Quantity = Length.
Quantity = Number of Units.
Quantity = Weight.

Importance of Quantity Survey:

1. Quantity survey is essential to estimate before the construction starts the probable cost of construction for the complete work. The construction cost includes cost of materials, cost of transportation, cost of labor, cost of scaffolding, cost of tools and plants, establishment and supervision charges, cost of water, taxes and reasonable profit of the contractor, etc. The estimate is required in inviting tenders for the works and to arrange contract for a complete project.

2. Quantity survey is required to estimate the quantities of the various materials required and the labor involved for satisfactory completion of a construction project.

3. It is also useful to check the works done by contractors during and after the execution. Also the payment to the contractor is done according to the actual measurements of the completed part of each

item of work.

4. A complete quantity survey or estimate is useful to provide useful advice to clients on:

(i) Valuation of properties (land and building) for sale, purchase and mortgage etc.
(ii) Fixation of standard rent.
(iii) For insurance and claim for damages in a building.
(iv) For the process of resolving disputes by referring to a third party.

Types of Estimates and Quantity Survey

Preliminary or Approximate Estimate:

This is to find out an approximate cost in a short time. It is used to give an idea of the cost of a proposed project. This estimate helps the client or sanctioning authority to make decision of the

administrative approval.

The approximate cost is prepared from the comparison with similar works. The approximate cost can

be found by using methods that depends on the area or cubic content of a building and then multiplying this by an estimated rate for the unit of the area or cubic content. Approximate quantities of materials and labor required per m2 of the area for a proposed building also can be found.

Detailed Estimate:

After getting the administrative approval, this estimate is prepared in detail prior to inviting of tenders. The whole project is divided into sub-works, and the quantities of each sub-work are calculated separately. The dimensions of the required work are taken from the drawings of the project.

Quantity Estimates:

This is a complete estimate of quantities for all items during project implementation.

 Revised Estimate:

Prepared if the estimate exceeded by 5% due to the rates being found insufficient or due to some other reason.


Maintenance Estimate:

Estimating required quantities and cost of work to maintain a structure (road, building, etc.)