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# Preliminary estimate

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### Preliminary estimate

1. 1. TOPIC 1: PRELIMINARY ESTIMATES
2. 2. DEFINATION AND IMPORTANCE OF PRELIMINARY ESTIMATES DEFINATION  Defined as an activity in particular work to make possible offer to execute task base on a stipulated sum  Technique to forecast the possible cost incurred for a certain building or construction project via a systematic calculation employing certain method, prepare at early stage of the project  Is a part of the cost planning process that is controlling of the project cost at the design stage before any drawings are embarked upon.
3. 3. USE OF THE PRELIMINARY ESTIMATE METHOD  To ascertain the actual cost forecast of a project.  Assist the client in knowing to what extent he need to be financially committed to a particular project  Estimated is also function as a design guide whether the project to the allocation made either
4. 4. Cont’d  If the estimate is higher that the client budget for that particular project, the following could be carried out :-  The design could be altered to reduce the cost  Extra provisions are sought after or requested from the client  The project is postponed or cancelled
5. 5. Cont’d  If the estimate is low than the allocated sum, the following could be done  Accept the estimate  To modify the design and/or the specifications to increase the estimate appropriate to the provision set aside.
6. 6. METHOD FOR PRELIMINARY ESTIMATE  UNIT  CUBIC  FLOOR AREA
7. 7. METHOD WHEN IT IS USED NOTE UNIT OF MESUREMENT UNIT Inception feasibility Appropriate for project that have standard unit of accommodation, its commonly used to establish the cost limit for public sector project Cost/student Cost/classroom Cost/bed Cost/ chair CUBIC Outline proposal Used to calculate the volume of air- conditioned space or space which is given mechanical ventilation Cost/m3 FLOOR AREA Outline proposal Used extensively, can be used for almost all types of building Cost/m2
8. 8. THE SELECTION OF THE METHOD WILL DEPEND ON  The information and time to prepare the estimate  The experience of Quantity Surveyor  The total and type of cost data available
9. 9. UNIT METHOD  This method is also referred to as ‘cost according to building function’  Estimate the building cost base on the size depends on the population unit  Example: the total number of student in a school, total number of bed in a hostel or hospital and etc.  Easier method but the most unrefined.  Total population can be obtained from the client or the design team
10. 10. USAGE  The cost estimate is obtained by multiplying the number of accommodation for a new building with the cost per unit of accommodation based on a suitable building  The current unit of accommodation can be obtained by calculating from the sketch design or by obtaining information from the client.
11. 11. Example: Estimate the total cost to build a mosque to house a congregation of 500 individuals. From a suitable cost data, get the cost/ congregation of a similar mosque that has been updated. Lets us say that the cost is RM 1400.00/ congregation. Total cost = Number of accommodation x cost/congregation 500 individuals x 1,400 = RM 7000,000.00
12. 12. CUBIC METHOD  In Malaysia this method is seldom or almost never used  Only in certain case, it is utilized  To calculate the space which is need to be air- conditioned  To calculate the space that needs mechanical ventilation
13. 13. USAGE  Measure the volume of the new building and its volume is then multiplied with the suitable price rate per m3  Unrelated works is to be volume must be calculated separately  The volume of the building is calculated as follows: Volume = length x width x height
14. 14. i. Height of pitch roof from the top surface of the foundation to half apex / height of roof ii. Height of flat roof From the top surface of foundation to 600mm above the flat roof or parapet wall (which is higher)
15. 15. L W Flat roofPitch roof
16. 16. Example Estimate the total cost to build a 2-storey bungalow if the construction cost/m3 of a similar construction is RM 550.00. estimate the construction cost base on a) Pitch roof b) Flat roof
17. 17. 20.00 10.00 1.00 3.50 3.50 1.50
18. 18. a) Pitch roof Building volume = 20.00 x 10.00 x [1.00 +2(3.50) + ½ (1.50)] =20.00 x 10.00 x 8.75 =1750m3 Total building cost = volume x cost/m3 =1750m3 x RM550.00 =RM962,500.00
19. 19. b) Flat roof Building volume = 20.00 x 10.00 x [1.00 +2(3.50) + 0.60] =20.00 x 10.00 x 8.60 =1720m3 Total building cost = volume x cost/m3 =1720m3 x RM550.00 =RM946,000.00
20. 20. Floor area method  Make a preliminary estimate as most of the cost data are kept or are available in this form  The measurement for GFA must be similar between the new building and the analyzed building  Need to consider criteria in measurement of area  In the calculation the floor area of a building there are several criteria need to be taken 1. The actual area of the building 2. If the project offers a standard or different type of accommodation it is better for each to be priced separately 3. Unrelated work to the area, for example, external work must be priced separately
21. 21. Cont’d  The rate per m2 chosen must be current rate as building cost often differ  The site, external works, condition of contract, the quantity and the quality of equipment and others that related to the floor area must be calculated separately  It is clear and difficulty of this method lies in choosing the appropriate rate, which requires experience, observation and familiarity toward varied building types
22. 22. USAGE  The floor area of a building to be erected. Only the building used this floor area method. Other works may use other method like approximate quantity. Total cost = area x cost/m2 gross floor area (GFA) Area – calculate the area of the building. The measurement method differs according to practices Cost/m2 GFA – from similar building type and function
23. 23. EXAMPLE Estimate the cost of the building by referring to the plans given if the construction cost is RM 1,500/m2 25.00 8.00 10.00 3.00 15.00 5.00 25.00 10.00 10.00 7.00 5.00 Ground floor plan First floor plan
24. 24. CONT’D Floor area Ground floor 25.00 x 5.00 = 125.00 10.00 x 3.00 = 30.00 5.00 x 7.00 = 35.00 190.00 First floor 25.00 x 5.00 = 125.00 10.00 x 3.00 = 30.00 155.00 345.00 Total cost = area x cost/m2 Gross Floor Area = 1500.00 x 345.00 = RM 517,500.00
25. 25. UNIT CUBIC FLOOR AREA  Fast and easy  Easiest method to obtain cost limit to prepare the monetary allocations for several years to come  No necessity for drawings  The estimate can be prepared quickly  The client and architect easily understand the concept of floor area. most work items are appropriately associated with the concept of floor area rather than the volume method  Cost data easily available as most of the data from previous project most utilize this method ADVANTAGES
26. 26. DISADVANTAGES UNIT CUBIC FLOOR AREA  An unrefined method and in accurate. Only suitable to provide and overall approximate estimate  Does not take into account changes to plan, number of storeys and other factors related to design  Unrelated work concerning unit of accommodation has to be calculated separately.  Does not take into account changes to plan, height, of storey and the overall height of the building  Unrelated work to the volume has to be calculated separately  Does not help architect in design work as it is difficult to predict or to know the effects of the changes to specifications, design, etc. to the cost per m3  Difficult to obtain similar cost data  Does not take into account changes to plan, height, of storey and the overall height of the building as these factors effect the building cost  Other work which are not related to the floor area must be calculate separately  Difficult to calculate and allocate the cost for different site conditions, quality of materials, condition of contract and etc.