Quantity Surveying

Quantity Surveying

1.1 Definition of Quantity Surveying

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

1.2 Data Required for the Preparation of an Estimate or Quantity Surveying

1.2.1 Drawings

Complete and fully dimensioned drawings (i.e. plans, elevations, sections and other details) of the building or work in question are required.

1.2.2 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.

1.2.3 Rates

The rates of various 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.

1.2.4 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.

1.3 Importance of Quantity Surveying

1. Quantity surveying is essential to estimate before the construction starts the probable cost of construction for the complete work. The construction cost includes the 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 a contract for a complete project.

2. Quantity surveying 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 surveying or estimate is useful to provide useful advice to clients on:

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

1.4 Types of Estimates and Quantity Surveying

1.4.1 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.

1.4.2 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.

1.4.3 Quantity Estimates

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

1.4.4 Revised Estimate

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

1.4.5 Maintenance Estimate

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

1.5 Contracts

Contract is an agreement between two or more parties creating obligations that are enforceable or recognizable at law.

It establishes an obligation of each party to fulfil what it is agreed to perform.

1.5.1 Obligations of the employer

  1. Appointing of the engineer to administer the contract
  2. Provision of the site
  3. Provision of information, permits, and approvals
  4. Providing funds and making payments in accordance with the contract
  5. Participation in consultations with the engineer to agree with matters on claims or conflicts between parties.

1.5.2 Obligations of the Contractor

1. Execution and completion of the works and remedying any defects therein.

2. Provision of:

  1. Labor, materials, plant, and equipment needed
  2. Preparation of progress report
  3. Works program for execution, and updating it whenever required
  4. Setting out of the works
  5. Measurement and/or assisting the engineer to do so
  6. Records of his personnel and equipment
  7. Sample of materials specified
  8. Testing and re-testing
  9. Temporary works
  10. Facilities for other contractors working on the site
  11. Keeping the site clean, and remove rubbish

3. The contractor is required to:

  1. Sign the contract when he is called to do so
  2. Obtain and submit securities, guarantees, and insurance policies
  3. Ensure that his representatives will be available on-site at all times
  4. Prepare and submit the contractor’s document, including “as-built drawings” and manuals of operation and maintenance
  5. Attend to the engineer’s instructions
  6. Provide access to the employer’s personnel to enter the site
  7. Prepare and submit payment statement and documentation
  8. To uncover works for inspection when required
  9. Rectify (Correct) defective works
  10. Secure or compensate the employer against any claims
  11. Submit notices to the engineer whenever he encounters circumstances that may cause future claims
  12. Getting approval before assigning sub-contractors or partners of the works
  13. Respond for consultation with the engineer

4. Comply with the applicable laws, labor law and other local regulations.

1.5.3 Role of the Engineer

Usually the employer will enter into a consultancy agreement with the engineer to design and/or supervise the works.

The engineer shall have no authority to amend the contract.

Engineer role can be:

1. As the employer’s agent:

a. Administration of the contract – dealing with the procedures, provision of information and interpretations, issuance of variations, approval of samples, etc.
b. Cost accountancy and payments

2. As a supervisor:

The engineer must ensure that the work is being performed to fulfil the contract documents.

3. As a certifier:

The engineer is required to certify or approve the payments that should be paid by the employer to the contractor. Those payments should be made periodically, mostly on monthly basis, and should depend on the quantity of works finished by the contractor.

4. As a determiner:

The engineer must act as a mediator to help the parties towards agreement in issues such as claims for reimbursement of costs or extension of time.

5. Issuance of instructions and variations

Include: issuance of additional or modified drawings, actions in relation to defective works, issuance of clarifications, giving approval, and ordering variations.

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