ESTIMATING AND VALUATION

Prepared by
Er.
 UNIT 1 METHODS OF ESTIMATING
1.1 Definition, importance and objectives of estimation
1.2 System of units
1.3 Units of measurement and payments for items of
work and materials
1.4 Essentials of estimating
1.5 Methods of measurements of building and civil
engineering works based on codes (NBC and Indian
codes)
1.6 Subheads of various items of work
1.7 Multiple methods of taking out quantities: center line
method, long and short wall method, crossing
method
1.8 Abstracting bills of quantities
1.1 Definition, importance and objectives of estimation

Definition
• Estimate is the process of calculating or computing the
various quantities and the expected expenditure to be
incurred on a particular work or project.

• The estimate gives the probable cost of work.

• If the estimate is prepared carefully and correctly, there will

not be much difference between estimated and actual cost.
Importance of estimation

• To estimate probable cost of the work.

• To find the various types and quantities of material required.
• To find the various categories and quantities of labors
required.
• To give an idea of time required for the completion of the
work.
• To invite the tenders and quotations and to arrange contract.
• To control the expenditure during the execution of work.
• To help in fixation of standard rent and valuation of
properties.
1.2 System of units

• Units of different measurements are mainly categorized for

their nature, shape and size and making payments to the
contractor.
• Basic units of measurements are:
1. Voluminous work = Cu.m
2. Surface work = Sq.m
3. Long and thin work = Rm
4. Piece work = no.
1.3 Units of measurement and payments for items of
work and materials
1.4 Essentials of estimating

Major data required are:

a. Detailed drawings
b. Detailed specifications
c. Rates
d. Mode/Method of measurement
a. Detailed drawings
• Drawings are required for the calculation of the quantities of
the materials.

• The drawings showing plans, elevations, different section

and other relevant detail with clear and complete dimensions
are very essential before preparing estimate.

• It will be better if there is municipal drawing and

construction drawing as well
b. Detailed specifications
• Specification describes the nature and class of the work,
material to be used, workmanship and is very important for
execution of work.

I. General Specification
• This gives a general idea about the nature, quality, class and
material in general terms to be used in various types of work.

II. Detailed Specification

• These gives the detailed description of the various items of
work laying down the quantities and quantities of materials,
their proportion, method of preparation, workmanship and
execution of work.
c. Rates
• Rates are essential for the computation of estimate by
multiplying quantities of materials with unit rates.
• For preparing estimate, the unit rates of each items of work
are required.

• Unit rates of each item arrive from:

i. The rates of various materials to be used in construction.
ii. The cost of transport materials.
iii. The wages of labour.
d. Mode/Method of measurement

• Update mode of measurement for standard deduction or

additions are also necessary to determine the correct
quantities of work.
1.5 Methods of measurements of building and civil
engineering works based on codes (NBC and Indian
codes)

• The rules for measurement of each item are invariably described in

code.
• However some of the general rules are listed below;

1. Measurement shall be made for finishing items of work and

description of each item shall include materials, transport,
labour, fabrication tools and plant and all types of overheads for
finished the work in required shape, size and specification.

2. In booking, the order shall be in sequence of length, breadth and

height or thickness.
3. All works shall be measured subject to the following
tolerances;
• Linear measurement shall be measured to the nearest 0.01m.
• Areas shall be measured to the nearest 0.01 sq.m (except steel
work area = 0.001 sq.m)
• Cubic contents shall be worked out to the nearest 0.01 cum.
(except wood = 0.001 cum)

4. Same type of work under different conditions and nature

shall be measured separately under separately item.
5. The bill of quantities shall fully describe the materials,
proportions, workmanships and accurately represent the
work to be executed.

6. In case of masonry (stone or brick) or structural concrete,

the categories shall be measured separately and the heights
shall be described as:
• From foundation to plinth level
• From plinth to first floor level
• From first floor to second floor level and so on.
Degree of accuracy
• Generally, the degree of accuracy in calculations depends upon the
rate of the item of work; items of work with high rates shall be
measured more accurately than items of work with lower rates.

a. The dimensions shall be taken to the nearest 0.01m except for

• Thickness of slab which shall be measured to the nearest 0.005m
• Woodwork to the nearest 0.002m
• Structural steelworks to the nearest 0.001m and
• Thickness of roadwork (where the thickness is less than 200mm) to
the nearest 0.005m.
b. Areas shall be worked out to the nearest 0.01 sq.m. For steel
works, areas excluding cross sectional measurement
shall be worked out to the nearest 0.001 sq.m

c. Cubic contents shall be worked out to the nearest 0.01 cum

except for woodwork, which shall be worked out to the
nearest 0.001 cum

d. Weights shall be worked out to nearest 0.1 kg.

1.6 Subheads of various items of work

• Earthwork
• Concrete (RCC and PCC)
• Masonry work (Brick or stone)
• Wood work
• Flooring
• Finishing work (plaster, painting, roofing..)
1.7 Multiple methods of taking out quantities: center line
method, long and short wall method, crossing
method

• The quantities of buildings work can be worked out by any of

following method;
a. Center line method
b. Long wall and short wall method
c. Crossing method
a. Center line method

• This method is suitable for walls of similar cross sections.

• Here, the total centre line length is multiplied by breadth and
depth of respective item to get the total quantity at a time.
• When cross walls or partitions or verandah walls join with
main all the centre line length gets reduced by half of breadth
for each junction.
• Such junction or joints are studied carefully while calculating
total centre line length.
• The estimate prepared by this method is most accurate and
quick.
b. Long wall and short wall method

• In this method, the wall along the length of room is considered to

be long wall while the wall perpendicular to long wall is said to be
short wall.

• To get the length of long wall or short wall, calculate first the
centre line of lengths of individual walls.

• Then the length of long wall (out to out) may be calculated after
adding half breadth at each end to its centre line length.
• Thus the length of short wall measured into in and may be found
by deducting half breadth from its centre line length at each end.

• The length of long wall usually decreases from earth work to brick
in super structure while the short wall increases.

• These lengths are multiplied by breadth and depth to get quantities.

c. Crossing method

• In this method, length and breadths of the masonry walls of

plinth level are taken (internal dimension of room + thickness
of wall) for calculating quantities.

• The center line method is obtain by calculating the overall

perimeter of building and subtracting four times of thickness
of wall on it.
1.8 Abstracting bills of quantities
Bill of quantity
• It is the statement of various items of work giving the
description, quantity and unit of rate.
• It is a document used in tendering process which includes the
materials and labors with their respective costs.
• It is also detail document about the terms and condition of the
construction or repair contract and itemizes all work to
enable a contractor to price the work for which he/she is
bidding.
• It is same as abstract of estimated cost but the rates and
amount columns are left blank; when rates and columns are
filled up and totaled, give the estimated cost.
Abstract of cost
• Abstract of cost can be defined as total cost required for
construction work, which is obtained by summation of all
cost required for particular works.
Thank you