Quantity Survey and Estimation basic terms

Basics of QSC

1. SAGAR INSTITUTE OF SCIENCE & TECHNOLOGY Gandhinagar, BHOPAL Advance Quantity Surveying and Costing Department of Civil Engineering

2. Estimation An  estimate  is a calculation of the quantities of various items of work, and the expenses likely to be incurred there on. The total of these probable expenses to be incurred on the work is known as estimated cost of the work . The estimated cost of a work is a close approximation of its actual Estimation and costing in Civil deals with calculating the quantities and its expected expenditure to be incurred from particular project. 

3. Why do we need Costing and estimation? It helps us to decide whether rate of proposed project match meets our funds available for the project. Avoids unwanted loss incurred in project. Helps in inviting tender and quotation to arrange contract. Gives an idea about time and its schedule of work required for completion of project.

4. What is Estimating and Costing? Estimating” is done before executing any project or job. “Costing” is done after execution of any project or job. ... It is an art of calculating the quantities of various items of work that is required to be executed for completion of any work and finding the cost of each items. What is the purpose of Estimating and Costing? Estimation (or estimating) is the  process  of finding an estimate, or approximation, which is a value that is usable for some purpose even if input data may be incomplete, uncertain, or unstable. The value is nonetheless usable because it is derived from the best information available.

5. Most Important term’s used in Estimation Measurement Book Abstract sheet Schedule of rate Drawing of construction

6. Measurement Book “Measurement Book” is an important document in which measurements are recorded for the work done by the contractor, or for the materials received at the site or services rendered • MB belongs to the Division – and is serially numbered recording to whom issued, date of issue, etc (DEE/ SDO) Contractor payments are made based on the measurements recorded in the MB It is considered very important accounts record and maintained very carefully and accurately and form substantial evidence in the court of law - should need arises Measurements are written legibly so that transactions are readily traceable

7. Recording of Measurements Each set of measurements should commence with entries – Work Name as given in the estimate / agreement Work location Contractors Name Agreement Number and date Work commencement date Work completion date Measurement recording date

8. Measurement Book Serial No Item Description No Length Width/ Breadth Depth/ /Height /Thickness Qty Remarks

9. Writing the MB Manually Item specification is clearly written completely Actual Measurements executed - length, width, depth etc entered in the respective columns Quantity is then computed (executed) Possibility of errors are more since manual Writing Terminology in Measurement book

10. Abstract Sheet After the measurements are taken, abstract is prepared duly carrying forward the quantities to the abstract MB Advance Measurement Book Serial No Item description Rate Up to date bill Up to previous bill This month bill MB Page No Qty Amount Qty Amount Qty Amount Serial No Item Description Total Qty No Rate Total Rate Remarks

11. Type of estimate Preliminary Cost Estimate/Rough cost estimate Plinth Area Cost Estimate Cube Rate Cost Estimate Approximate Quantity Method Cost Estimate Detailed Cost Estimate Revised Cost Estimate Supplementary Cost Estimate Annual Repair & Maintenance Cost Estimate

12. Preliminary Cost Estimate/Rough cost estimate The preliminary cost estimate is also called an  abstract cost estimate or approximate cost estimate or budget estimate.  This estimate is generally prepared in initial stages to know the approximate cost of the project. By this estimate, the competent sanctioning authority can decide the financial position and policy for the administration section. preliminary estimates are prepared with reference to the cost of similar type projects in a practical manner. In this estimate, the approximate cost of each important item of work is displayed individually to know the necessity and utility of each item of work. The items of work include the cost of lands, cost of roads, electrification, water supply costs, cost of each building, etc.

13. Benefits of Preliminary Estimates To get rough idea about total construction cost Get beforehand information regarding the major material required. Helps in quick planning and initial execution of project. Helps in managing the project budget and costs. Allows the clients to choose the best contractor.

14. Plinth Area Cost Estimate Plinth area cost estimate is prepared on the basis of plinth area of building which is the area covered by external dimensions of building at the floor level  and plinth area rate of building which is the cost of similar building with specifications in that locality. Plinth area estimate is obtained by multiplying plinth area of building with plinth area rate. For example if we require plinth area estimate of 100 sq.m in a particular locality and plinth area rate of a building in same locality is 2000 per sq.m then plinth area estimate is 100 X 2000 = 200000. Open areas, courtyards, etc. are not included in the plinth area. If the building is multi-storied, the plinth area estimate is prepared separately for each floor level.

15. Cube Rate Cost Estimate Cube rate cost estimate of a building is obtained by multiplying plinth area with the height of building. Height of building should be considered from floor level to the top of the roof level. It is more suitable for multi storied buildings. This method of estimation is accurate than plinth area method.  The rate per cubic meter is taken into consideration based on the costs of similar type of buildings situated in that location. Foundation, plinth and parapet above the roof level are not considered in this type of estimate.

16. Approximate Quantity Method Cost Estimate In approximate quantity method cost estimate, the total wall length of the structure is measured and this length is multiplied by the rate per running meter which gives the cost of the building. The rate per running meter is calculated separately for the foundation and superstructure. In case of foundation, rate per running meter is decided by considering quantities such as excavation cost, brick work cost up to plinth. While in case of superstructure quantities like brickwork for wall, wood works, floor finishing etc. are considered for deciding rate per running meter.

17. Detailed Cost Estimate Detailed cost estimate is prepared when competent administrative authority approved the preliminary estimates. This is very accurate type of estimate. Quantities of items of work are measured and the cost of each item of work is calculated separately. The rates of different items are provided according to the current workable rates and total estimated cost is calculated. 3 to 5 % of estimated cost is added to this for contingencies as miscellaneous expenditure. The detailed Estimated should consist following details and documents.

18. Report General Specifications Detailed Specifications Drawings/plans – layout plans, elevation, sectional views, detailed drawings etc. Designs and calculations – In case of buildings design of foundations, beams, slab etc. Schedule of rates

19. Revised Cost Estimate Revised cost estimate is a detailed estimate and it is prepared when the original sanctioned estimate value is exceeded by 5% or more. The increase may be due to sudden increase in cost of materials, cost of transportation etc. The reason behind the revision of estimate should be mentioned on the last page of revised estimate.

20. Supplementary Cost Estimate Supplementary cost estimate is a detailed estimate and it is prepared freshly when there is a requirement of additional works during the progress of original work. The estimate sheet should consists of cost of original estimate as well as the total cost of work including supplementary cost of work for which sanction is required.

21. Annual Repair Cost Estimate The annual repair cost estimate is also called as  annual maintenance estimate  which is prepared to know the maintenance costs of the building which will keep the structure in safe condition. Whitewashing, painting, minor repairs, etc. are taken into consideration while preparing annual repair estimate for a building.

22. Important term used in Estimation Contingencies :-While planning any construction project, finalizing a budget is one of the major steps in planning a successful project. Designing and planning to project considering where to spend money and budgeting for all the work takes both attention to detail and complete scope of the project. However, all estimate is correct and accurate there is some unforeseen issues or items that come up where additional work will be needed. This is where a contingency budget becomes critical.

23. To meet such unforeseen expenses an additional amount of 3 to 5% of the estimated cost of the work is provided in the total estimates. Miscellaneous incidental expenses that cannot be classified under any subhead item, are met the amount provided under contingencies. For example, there is an item of work cement plastering in a 1:3 mix ratio with neat cement finish, but during execution, it is desired to provide nosing at the end of steps. As there is no allocation of funds for this small work, the cost of sub work may be met up from the contingency fund.

24. WORK CHARGED ESTABLISHMENT: During the construction of a project considerable number of skilled supervisors, work assistance, watch men etc., are employed on temporary basis. The salaries of these persons are drawn from the L.S. amount allotted towards the work charged establishment. that is, establishment which is charged directly to work. an L.S. amount of 1½ to 2% of the estimated cost is provided towards the work charged establishment .

25. Departmental charge When the engineering department takes up the works from the other department a percentage amount of 10% to 15 % of estimated cost is charged to meet the expense of establishment , designing, planning and supervision is known as departmental charge.

26. Contingencies – Indicates incidental expenses of miscellaneous character which cannot be classified under any distinct item. (3% to 5% of the estimated cost is provided to allow for contingencies) Work-charged Establishment – Work-charged employees are temporary staff whose services are terminated at the expiry of sanctioned period but usually one month notice is given. (1.5% to 2% of the estimated cost is added) Tools and Plants – Normally contractor has to arrange tools and plants. (1% to 1.5% of estimated cost is provided) Centage charges or Departmental charges – Also known as Supervision charges for works. To meet the expenses of establishment, designing, planning, supervision etc. (10% to 15% of the estimated cost). When engineering department takes up work of other department.

27. Sub-Head items of work – Works like earthwork, concrete work, brick work etc. Under each sub head there are different items of work. Sub-Work – Large project may consist of small buildings. Detailed estimate of each sub-work is prepared separately. Administrative Sanction/ Approval – It is the formal acceptance by the department concerned of the proposal. After the approval, design, estimates etc. are prepared and thereafter execution of work.

28. Expenditure Sanction – It represents allotment of money to meet the expenditure. It is usually accorded by Finance Department. Technical Sanction – It is the sanction of the detailed estimate, design calculation, quantities of work etc. Technical sanction is accorded by engineering department and execution of work is carried out thereafter. Quantity Survey – It means estimating of quantities of different items of works. Plinth Area – It is the built up covered area of a building measured at floor level of any storey by taking external dimensions of the building at the floor level.

29. Floor Area :-It is obtained after deducting area of walls from the plinth area of building. It should include: Door and other openings Intermediate pillars and supports Circulation Area – It is the floor area of verandahs, passages, corridors, balconies, staircases, lift etc. which are used for movements of persons using the building. It is further classified into Horizontal and Vertical. Carpet Area – It is the useful area of the building. It is determined after deducting Circulation Area Sanitary Accommodations Kitchen, Pantry, Stores For office building approximate 60% to 75% of plinth area For residential buildings approximate 50% to 65% of plinth area

30. Site Plan – Plan showing orientation of building, boundaries of land, position of roads, drains, sewer line, water pipelines and adjoining plots of lands. North direction is also shown on one corner of site plan) Layout Plan – Plan showing proposed buildings, structures etc. showing their locations, size and orientations. Roads, drains, pipe lines , electric lines, parks etc are shown. The boundary, main approach roads and adjoining areas are also indicated.

31. Report gives brief information of whole project. It should consist of the following : Brief history (with proposal) Necessity and feasibility of project Selection of site Survey Brief description of works Nature of soil, topography of land etc. Basis of design calculations Arrangement for water supply, sanitation and electrical installations etc. Roads and drains Temporary accommodations for staff, labour etc included in misc. Manner of execution Total cost and how to be financed Return or revenue income Rent statement Time of execution

32. Electrification, Sanitary & Water Supply In building work for internal electrification, sanitary and water supply works a percentage about 20 % of the estimated cost of building is provided . The provision for this are as follows For Sanitary & water supply work :- 8% of building cost For Electrification:- 8 % of building cost For Electric fan :- 4% of building cost

33. Cost of electrification may vary from 5% to 8% Cost of water supply & sanitation may vary from 5% to 8% And cost of fan may vary from 3% to 4%

34. Complete set of estimation should have Title page of giving information about department, division, District of sub division, estimate no, name of work, amount of estimate Index of content, plan & drawing Report Design calculation General Specification Detailed specification Analysis of rate of different item Details of measurement and calculation of quantity Abstract of estimated cost Drawing plan elevation and section.

35. Schedule of Rates – It is a list of rate of various items of works maintained by engineering department under the name “Schedule of Rates Book”. “Road Metal Rate Book” is also maintained by PWD. S.O.R is the list of rates of various items of work. To facilitate the preparation of estimates , and also to serve as guide in setting rates in connection with contract agreements .It is maintained in the form of printed books known as schedule of Rates ( S.O.R ).

36. It consists of group of items such as excavation items , concrete items , demolition items , plumbing items , electrification works etc. S.O.R is prepared by Central Public Works Department (CPWD) which is premier construction organization of Government of India The S.O.R consists rates about 2500-3000 items under different subheads like Building work , Water supply , Sanitary etc.

37. Various category of labors /artisans are required for construction. The rates may vary from place to place. Sr no. Type of labors Rates ( per day ) Mistry 400 Mason 300 Male labor 200 Female labor 180 Carpenter 300 Blacksmith 300 Painter 250 White Washer 200 Plumber 300 Watch Man 200

38. Driller 460 Assistant Driller 378 Special Heavy labor for driving sheet pile 460 Water meter Reader 336 Helper for Rig 321 Electrician with “C” Certificate 336 Electrician 588 Electrician with ITI and “C” Certificate 563 Electrician with ITI with “B” certificate 504 Electrician with ITI 460 Pump operator with ITI 460

39. Pump operator without ITI 460 Laboratory attainder SSLC / 10th Std Passed 321 Filter bed operator 563 Filter Bed operator with ITI 460 Filter Bed operator without ITI 391 Carpenter Class 1 475 Carpenter Class 2 444 Cleaner Group1 259 Cleaner Group 2 245 Filter 1 class 438 Filter 2 class 409 Floor Polisher 382

40. Prepare a preliminary estimate of a building project with a total plinth area of 1500 sq m . Plinth area rate 950 per sq m Extra for special architectural treatment 1% of building cost Extra for water supply and sanitary 1.5% of building cost Extra for internal installation 14% of building cost Extra for service 6% of building cost Contingencies 3% Supervision charges 8 %

41. Solution:- Building cost :- 1500 Sq m @ 950 per Sq m =1500*950=1425000/- special architectural treatment (1425000*1.5)/100=21325/- internal installation (1425000*14)/100=199500/- water supply and sanitary (1425000*5)/100=71250/- Other Service (1425000*6)/100=85500/- Total (1425000+21325+199500+71250+85500) =1802575/- Contingencies (1802575*3)/100 = 54077/- Supervision charges :- (1802575*8)/100=144206/- Grand total:- 2000858/-