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Presentation on theme: "PREPARED BY: NOR AZAH BINTI AZIZ KOLEJ MATRIKULASI TEKNIKAL KEDAH 1."— Presentation transcript:


2  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. (close approximation of its actual cost)  The agreement of the estimated cost with the actual cost will depend on accurate use of estimating methods and correct visualization of the work, as it will be done. 2

3 To give a reasonably accurate idea of the cost An estimate is necessary to give the owner a reasonably accurate idea of the cost to help him decide whether the work can be undertaken as proposed or needs to be curtailed or abandoned, depending upon the availability of funds and prospective direct and indirect benefits. 3

4 1. Estimating Materials From the estimate of a work it is possible to determine what materials and in what quantities will be required for the work so that the arrangements to procure them can be made. 2. Estimating Labor The number and kind of workers of different categories who will have to be employed to complete the work in the specified time can be found out from the estimate. 4

5 3. Estimating Plant An estimate will help in determining amount and kind of equipment needed to complete the work. 4. Estimating Time The estimate of a work and the past experience enable one to estimate quite closely the length of time required to complete an item of work or the work as a whole. Whereas the importance of knowing the probable cost needs no emphasis, estimating materials, labor, plant and time is immensely useful in planning and execution of any work. 5

6 Measuring - A process of evaluating items from prepared working drawing n noting in the BOQ form. - This evaluation is to obtain the items quantity in specific unit. 6

7  Method of measuring are; i) linear ii) area iii)volume iv)weight v)number 7

8  Multiple items measured linearly  Measure items with fixed cross section  Estimate item price based on linear item’s measurement such as length of pipe, length iof strip foundation and length of external wall of a building  Unit : metre ( m) 8

9  Measure item such as pavement surface, plaster, brick wall, site clearing, formwork and so on  Measurement that is required to record are length and width, width and length and height.  Unit : squre metre ( m 2 ) 9

10  Involve item such as soil excavation for foundation, concreting for beam, slab and others  Sides measurement are length, width and depth for item with three surfaces  Structures like pyramids, cone, spherical and cylindrical require measurement based on mathematical formula to calculate volume.  Unit : cubic metre ( m 3 ) 10

11  Applied when item estimated is based on weight  Applied for item such as reinforcement steel placed in the reinforced concrete structure  Unit : kilogram to metric tonne ( kg to tonne) 11

12  Applied for complex item where it is difficult to divide into small component and to estimate the price of each component.  Those items include electrical wiring such as lighting socket, fan point, door, window and precast concrete  Unit : Number ( No) 12

13 Type of reinforcement Hook (h)Bend (n)Symbol Mild steel12 d 8 d R or M.S High- yield steel15 d 9.5 d Y or H.Y Table : Reinforcement steel measurement linear method Diameter of reinforcementkg/m Table : Example of weight measurement of reinforcement 13

14  Item’s cost is divided into: i)material cost ii)Labour cost iii)plant and equipment costs iv)overhead cost and profit 14

15 i)Material cost -Material cost such as brick, roof tile, glass and iron -Estimated price depend on the latest marker price and location of site. 15

16 ii)Labour cost -A fee or wages to the workers after work has been completed. -Two classes of workers are; a.skilled worker b. general worker -The determination of fee depends on the labour constant 16

17 iii)Plant and equipment costs -Plant and equipment important to execute work effectively and quickly. -Two types; a. non machinery plant and equipment; ladder n wheel barrow b. machinery plant and equipment; lorry, bulldozer n concrete mixer 17

18 iv)overhead and profit cost - Include various type of payment related to the company’s management; a. salary of management personnel b. cost and office equipment depreciation cost c.allowances for company’s board of directors 18

19 There are 5 methods of preparing estimation for construction project; i)Volume ii)Floor area iii)Evaluation iv)Approximate value quantities v)Bills of quantities 19

20 -Based on the building length, width and height -The construction cost of the proposed building is the product of the volume of the proposed building and the cost rate per cubic meter 20

21 -Determined by multiplying the floor length to width ( measured from outer wall of the building) -Construction cost of the new building = x -Only considers the construction cost of the building. -Other construction work such as fence, road, drain and landscape are not included. Area of the new building the cost rate per cubic metre of the existing building 21

22  Carried out by counting the number of furniture, number of occupants.  For example, the unit to be calculated in construction of school is the number of chairs.  Every unit of the furniture is given the cost per unit based on the cost from the existing building.  Estimated cost = Cost per unitxNumber of the furniture for proposed building 22

23  Almost similar to the bills of quantities method  Carried out by identifying items, calculating quantity and calculating the item’s gross cost based on the working drawing.  Calculating cost are based on excavation work and concreting work. 23

24 A bill of quantities (BOQ) is a document used in tendering in the construction industry in which materials, parts, and labor (and their costs) are itemized. 24

25 It also (ideally) details the terms and conditions of the construction or repair contract and itemises all work to enable a contractor to price the work for which he or she is bidding. 25

26  Most accurate method compared to the others method  QS take off accurately the quantity of measured items from the working drawing 26

27 Step in preparing ; 1.interpreting drawing 2.dimensioning and taking off the quantities 3.grouping of quantities 4.estimating cost BILL OF QUANTITIES METHOD 27

28  Dimensioning and taking off quantities is a process of taking dimension, adding up and multiplying the items dimension.  Use the quantity measurement form -consist 2 parts -each part contains 4 column - they are multiplying, dimensions, total and work description columns. 28

29 A DCBA CBD DIMENSION DESCRIPTION Record the number to be multiplied based on the number of repeated item Record the dimension of items Record the total measurement of linear, area, volume and number of items Record the description operation of the measured items briefly n accurately 29

30 ii)Area measurement Topsoil excavation 100 mm thick beginning from the ground level with length and width Topsoil excavation 100 mm thick beginning from the ground level mm mm x 50 mm thick sawn and treated timber for roof rafter 2.50 m DIMENSION DESCRIPTION i)Linear measurement 100 mm x 50 mm of thick sawn and treated timber for a 2.5 m long roof rafter 30

31 iv)Weight measurement the weight of steel reinforcement of 7m long with a diameter of 32 mm 32 mm in diameter mild steel reinforcement in column x kg/m = kg excavating trench not exceeding 1.5 m deep m 3 DIMENSION DESCRIPTION iii) Volume measurement excavating trench not exceeding 1.5 m deep of 22.0 long, 0.70 wide and 1.3 deep 31

32 5 5 Ceiling fan as described in the specification DIMENSION DESCRIPTION v)Number measurement 5 number of ceiling fans 32

33  Abstracting quantities is carried out by abstracting  Transfer all measurement and work descriptions from the dimension form to abstract form  Purpose of abstracting – to divide and group all particulars and work descriptions according to subheading and the quantities are rounded up 33

34 34 Trench excavation for strip foundation beginning from the prepared level, not exceeding 1.50 m deep; backfilling the soil and compacting it; transporting and dumping surplus soil at an average distance of 50 m from the site. Unit ( m 3 ) page ( from the dimension form) m 3 ( rounded up to the nearest whole number)

35  When abstracting work is completed, the work description, unit and work quantities are recorded in the bills of quantities form top estimate the cost. 35

36 ItemDescription of workUnitQuantityRateTotal RMSenRMSen ATrench excavation for strip foundation beginning from the prepared level, nor exceeding 1.5 m deep; backfilling the soil and compacting it; transporting and dumping surplus soil at an average distance of 50 m from the site. m3m PROJECT :


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