1.
Chapter 2
Types of Estimate
1) Preliminary Estimate/Approximate Estimate
It is also called approximate or rough estimate
This type of estimate is carried out to find out the
estimated cost in very short time.
Detailed drawing may not be mandatory.
This provides decision for the financial investment and
its justification by comparing investment of the different
project
This is prepared from practical knowledge and
comparison of similar works constructed recently

2.
Preliminary estimate is prepared in various ways for
different Wocks and structure
For Building
 Per unit basis example for bed for hospital, for seat for cinema halls, for class
room for school
 plinth area basis
 cube content basis
 approximate quantity basis
For irrigation works
 per kilometre basis
 command area basis
Road and Highways
 for kilometre basis depending upon nature class of road width of road thickness of
metalling
Bridge and Culvert
 for running metre depending upon roadway with nature and depth of foundation
type of structure
Water Supply and Sanitary Works
 on the basis of for head population served
 on the basis of area covered
Overhead Water Tanks
 on the basis of capacity for liter or gallion basis

3.
Purpose of Preliminary Estimate
To investigate feasibility
To save time and money
To investigate benefit
To obtain administrative approval
For insurance and tax schedule

4.
Types of Preliminary Estimate
a) Plinth Area Estimate
b) Cube Rate Estimate
a)Plinth Area Estimate:
Plinth area estimate is prepared by multiplying plinth
area by plinth area rate.
Civil cost(Building cost)= Plinth area ⅹ Plinth area rate
Plinth area = Carpet area(50-65)%+Circulation area(20-
30)%+ Wall area(5-10)%

5.
b) Cube Rate Estimate
This is the approximate estimate for the building
and is based on the cubical content of the
building and the cube rate
The cube rate is obtained from the cost of the
building having similar specification and the
construction in the same locality.
Cubical content is found out by multiplying by L,
B and H of the building.
Height is taken from the floor level to the top for
flat roof and upto mid height for sloped roof
This method is more accurate than plinth area
estimate.

6.
2) Detailed Estimate
 After getting Administrative approval on
rough cost estimate, detailed estimates are
prepared.
This is the accurate estimate and consists of
working out the quantities from detailed
drawing(plan, section, elevation) and
specification.
The detailed estimate shall also provide for
the cost of approach road, water supply,
electric installations and acquisition of land
etc.,

7.
Detailed estimate is prepared in two stages
1. Detailed of measurement and calculation of quantities
The whole work is divided into different items of work as
earthwork , concrete work , brickwork, RCC , finishing work etc.
and the items are classified under different sub head.
Details of measurement of each item of work are taken out and
quantities under each items are computed in details of
measurement form
Details of measurement form
Items no. Description of work No. L B H Q Remarks
1 Earthwork in
excavation
1 2 2 1 4m3
2 Soling 1 2 2 4m2

8.
2. Abstract of estimated cost
The quantities of each items of work and the
workable rate is used to find the total cost of the
work.
These quantities, rate and the total cost is
workout in a prescribed form called abstract of
estimate form.
Abstract form
Items no. Description of work Quantity Unit Rate(Rs) Amount(Rs)
1 Earthwork in
excavation 4
m3 1000 4000
2 Soling 4 m2
50
200

9.
Data Required for Preparation of Detail Estimate
i) Drawing:
 Drawings are the basis from which quantities of
various items of work are calculated.
Drawing should show plan ,elevation and sectional
details wherever necessary.
 The drawing should be fully dimensioned.
ii) Schedule of rates:
The rate of various items of work, material, labour
are needed to find the estimated cost.
 The quantities of different items of work are
calculated from drawing and then multiplied by
rates

10.
iii) Specification:
 It is a part of contract document containing information
regarding the quality of material and workmanship.
Types of Specification
a) General or brief specification
 It contains short description about the work to be performed
and the material to be used.
 Used by designed team for estimation
 The nature and class of works are described
b) Detailed specification
 This describes every items of works separately.
 These are written as per BoQ ,which specify material to be
used, its quality, workmanship
 These are written as far as possible in the same sequence of
order as the work is carried out.

11.
iv)Methods of measurement
Modes of measurement are necessary to
determine the correct quantity.

12.
3) Revised estimate
It is a detail estimate which are prepared when
the sanction estimate is likely to exceed by more
than 5%.
This may be due to rate being insufficient or from
any cause except for the alteration of structural
component.(Due to change in rate and change in
quantity of material)
The revised estimate should show the
comparative statement of different items of
works; its quality; and rate(cost) under original
and revised estimate side by side
Additional or revision of drawing is not necessary

13.
Comparative Statement Form
Items Description
of work
Existing Estimate Revised Estimate Reason
Q Rate Amount Q Rate Amount
1 E/W 10cum 450 4500 15
cum
450 6750 Q changed but rate being
same
2 PCC(1:2:4) 1 cum 12000 12000 1 cum 1500
0
15000 Q same but rate being
changed

14.
4) Supplementary estimate
This is the detailed estimate and is prepared
when the additional work are required to be
supplement the original work or when further
development is required during the progress of
the work.
Supplementary estimate is prepared due to
material deviation of structural nature from the
design originally approved.
This is estimate for the additional work only.
Additional or revision of drawing may be
necessary
Comparative abstract form is not required.

15.
5) Annual Repair and Maintenance Estimate
It is a detailed estimate and is prepared to
maintain the structure or work in same ,
economical and serviceable condition after
completion of project.
An estimate is prepared for the items which
requires renewal, replacement, repair etc.
The cost of annual repair and maintenance
estimate should not exceed more than 1.5% of the
capital cost
For building it includes colour washing,
maintenance of plumbing works, seepage etc.

16.
6)Extension and Improvement Estimate
If further changes and extension are required to be
made in old work , the cost of which can’t be met
out of annual repair and maintenance estimate , a
detailed estimate of additional work is prepared,
called extension and improvement estimate.
It requires
a)Existing Drawing
b)Drawing of additional or changed works
c)Rate

17.
7) Complete estimate
This is an estimated cost of all items which are
related to the work in addition to the main contract
or to the detailed estimate.
This includes the following cost
a) Cost of land
b) Cost of legal expenses between owner and
contractor
c) Engineering fees(Cost for preparation of plans,
design, estimate, and sanction fees
d) W/S sanitary and electrification charge
e) Contingencies
f) Miscellaneous viz; transportation cost etc.

18.
Thumb Rule for Carpet Area
For office building
Carpet area =60 to 75% of plinth area
For Residential Building
Carpet area =50 to 65% of plinth area
Wall area = 5 to 10% of plinth area
Water supply = 4 to 5%
Sanitary charge = 4 to 5 % of building cost
Electrification charge = 9 to 12% of building cost

19.
Numerical
1)Prepare preliminary estimate of a building
having plinth area 5600sqm and plinth area rate
Rs 30000 .
i)Water supply and sanitary charge 8% of
building cost.
ii)Electrification charge 9%of the buiding cost.
iii) Contingencies charge 3% of overall cost.
iv) Supervision charge 5% of overall cost.

20.
solutions
1) Building cost = Plinth area ⅹ Plinth area rate
= 5600 ⅹ 30000
= Rs 168000000
2)Water supply and sanitary charge =8% of B.C
=
8
100
ⅹ 168000000
= Rs 13440000
3)Electrification charge = 9% of B.C
=
9
100
ⅹ 168000000
= Rs 15120000

21.
A) Overall cost =1 + 2 +3
= Rs168000000+Rs13440000+Rs15120000
=Rs196560000
4) Contingencies charge=3% of overall cost
=
3
100
ⅹ Rs196560000
= Rs 5896800
5) Supervision charge = 5% of overall cost
=
5
100
ⅹ Rs196560000
=Rs 9828000

22.
Total preliminary estimate
= overall cost +contingencies charge +
supervision
=Rs 9828000+Rs 196560000+Rs 5896800
=Rs 212284800

23.
2)Prepare a preliminary estimate of a building having
carpet area 1800sqm circulation area and wall area
being 30% and 10% of plinth area respectively.
Given
i) Plinth area rate = Rs 30000 per sqm
ii) W/S and sanitation charge = 8% of building cost
iii) Electrical installation charge = 9% of Building cost
iv) Contingencies and supervision = 8% of overall
cost.

24.
Solution
Let, plinth area of building = 𝑥 m2
Plinth area = Carpet area + Circulation area + wall area
𝑥 = 1800 +
30
100
𝑥 +
10
100
𝑥
𝑥 = 1800 + 0.3 𝑥 + 0.1 𝑥
𝑥 - 0 .4 𝑥 = 1800
𝑥 = 3000m2
i) B.C = Plinth area x Plinth area rate
B.C = 3000 x 30000
= Rs 90000000

25.
ii) Water supply and sanitary charge = 8% of B.C
= 8/100 x 90000000
= Rs7200000
iii) Electrification charge = 9% of B.C
= 9/100 x 90000000
= Rs 81,000,00
Overall cost= i + ii +iii
=Rs 10,53,000,00
Contingencies and supervision charge =8% of
overall cost
= 8/100 x 1053000
= Rs 8424000
Total cost of Building = O.C + Contingencies and
Supervision charge
= 105300000 + 8424000
= Rs 113724000

26.
Conversion of system of units
11
Length
1cm = 10mm
1m = 100 cm
1km = 1000m
1 inch = 2.54cm
1ft = 12 inch
1m = 3.28 ft
1 mile = 1.609 km
Area
1ropani = 16
aana=508.74sqm=5476s
qft
1aana = 4 paisa
1paisa = 4 daam
1 hectare= 104 m2
1 bigha = 20 kattha
1 Katha = 20 dhur
1bigha = 13.31 ropani
Weight
1 MT= 1000kg=1
tonne
1kg = 1000gm

27.
Numerical on Cube Rate method.
Q. A person Construct a building of plinth area equal
to 100 square metre on a plot of land in a certain
locality at a cost of 20 lakhs .The height of the
building from ground level to the top of the roof
is 3.5 metre and a parapet Wall of height equal to 80
cm is constructed on a terrace .Determine the cost of
similar building of plinth area equal to 135 square
metre to be constructed in the same locality by plinth
area rate and volume(cube) rate method.
Building cost=Cubical volume*cube rate