preliminaryestimate

8/12/2019 preliminaryestimate

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TOPIC 1:

PRELIMINARY

ESTIMATES


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DEFINATION AND IMPORTANCE

OF PRELIMINARY ESTIMATESDEFINATION

Defined as an activity in particular work to makepossible offer to execute task base on a stipulated sum

Technique to forecast the possible cost incurred for acertain building or construction project via a systematiccalculation employing certain method, prepare at earlystage of the project

Is a part of the cost planning process that is controllingof the project cost at the design stage before anydrawings are embarked upon.


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USE OF THE PRELIMINARY

ESTIMATE METHOD

To ascertain the actual cost forecast of aproject.

Assist the client in knowing to what extent heneed to be financially committed to aparticular project

Estimated is also function as a design guidewhether the project to the allocation madeeither


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Contd

If the estimate is higher that the client budgetfor that particular project, the following could

be carried out :-

The design could be altered to reduce thecost

Extra provisions are sought after orrequested from the client

The project is postponed or cancelled


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Contd

If the estimate is low than the allocated sum,the following could be done

Accept the estimate

To modify the design and/or thespecifications to increase the estimateappropriate to the provision set aside.


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METHOD WHEN IT IS USED NOTE

UNIT OF

MESUREMENT

UNIT Inception feasibility

Appropriate for projectthat have standard unitof accommodation, itscommonly used to

establish the cost limitfor public sectorproject

Cost/studentCost/classroomCost/bedCost/ chair

CUBIC Outline proposal

Used to calculate the

volume of air-conditioned space orspace which is givenmechanical ventilation

Cost/m3

FLOOR

AREA

Outline proposalUsed extensively, canbe used for almost all

types of building

Cost/m2


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THE SELECTION OF THEMETHOD WILL DEPEND ON

The information and time to prepare theestimate

The experience of Quantity Surveyor

The total and type of cost data available


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UNIT METHOD

This method is also referred to as cost according tobuilding 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 orthe design team


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USAGE

The cost estimate is obtained by multiplying thenumber of accommodation for a new building withthe cost per unit of accommodation based on a

suitable building

The current unit of accommodation can be obtainedby calculating from the sketch design or by

obtaining information from the client.


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Example:

Estimate the total cost to build a mosque to house acongregation of 500 individuals.

From a suitable cost data, get the cost/ congregation of asimilar 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


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CUBIC METHOD

In Malaysia this method is seldom or almostnever 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


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USAGE

Measure the volume of the new building andits volume is then multiplied with the suitable

price rate per m3Unrelated works is to be volume must be

calculated separately

The volume of the building is calculated as

follows:Volume = length x width x height


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i. Height of pitch rooffrom the top surface of the foundation tohalf apex / height of roof

ii. Height of flat roofFrom the top surface of foundation to 600mmabove the flat roof or parapet wall

(which is higher)


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L

W

Flat roofPitch roof


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Example

Estimate the total cost to build a 2-storey bungalow if theconstruction cost/m3 of a similar construction is RM550.00. estimate the construction cost base on

a) Pitch roof

b) Flat roof


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20.00

10.00

1.00

3.50

3.50

1.50


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a) Pitch roof

Building volume = 20.00 x 10.00 x [1.00 +2(3.50) + (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


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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


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Floor area method

Make a preliminary estimate as most of the cost dataare kept or are available in this form

The measurement for GFA must be similar betweenthe new building and the analyzed building

Need to consider criteria in measurement of area

In the calculation the floor area of a building there areseveral criteria need to be taken

1. The actual area of the building

2. If the project offers a standard or different type ofaccommodation it is better for each to be priced separately

3. Unrelated work to the area, for example, external workmust be priced separately


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Contd

The rate per m2 chosen must be current rate asbuilding cost often differ

The site, external works, condition of contract, thequantity and the quality of equipment and others thatrelated to the floor area must be calculated separately

It is clear and difficulty of this method lies inchoosing the appropriate rate, which requiresexperience, observation and familiarity toward varied

building types


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USAGE

The floor area of a building to be erected. Only thebuilding used this floor area method. Other worksmay use other method like approximate quantity.

Total cost = area x cost/m2 gross floor area (GFA)

Area calculate the area of the building. Themeasurement method differs according to

practices

Cost/m2 GFA from similar building type andfunction

preliminaryestimate

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