Estimating part 1

ESTIMATING & COSTING
ARUN RAVI.K.R
Instructor, Draughtsman (Civil)
Part -1

01
LEARNING OBJECTIVES
What is Estimation?
02 Purpose of Estimating?
Technical Terms in Estimate
Classification of Estimates
03
04

What is Estimation?
An art of calculating or computing the various items of
work or project, to find out its approximate cost, the
quantity required of various materials, labour,
equipments etc. is called “Estimation.”

PURPOSE OF ESTIMATING
To Find the cost of construction work.

To calculate materials, Labour and Equipments for the
project

To invite tenders for work and arrange the contract.

To check out work done by contractors during execution.

To calculate the payment to the contractors according to
the actual measurement compared with existing estimate.

To calculate the sale value of buildings.

To fix standard rent.

For demolishing a building

 To Find the cost of construction work.
 To manage materials, Labour and Equipments
 To invite tenders.
 To check out the work during execution.
 To calculate the payments to the contractor
 To calculate the sale value of buildings.
 To fix standard rent.
 To demolishing a building

Project
A Project is a detailed requirements of proposal or scheme
consisting of
 Detailed technical report
 History
 Design data and calculations
 Detailed Drawings
 Detailed Specifications
 Schedule of Rates
 Project Estimates etc.
The project gives full details of all works involved for both
structural and financial requirements.

Quantity survey
Quantity Survey is the estimating of the quantities
of different items of works for a project.
These quantities are worked form the plan and
drawings of the structure.

Plinth area
Plinth area is the built up covered area of building measured at
floor level of any storey.
It is calculated by taking the external dimensions of the
building at the floor level excluding
 Plinth offsets if any
 Courtyard
 Open areas
 Balconies and
 Cantilever projections
Supported porches (other than cantilevered) are included in
the plinth area.

Plinth area
Question: Calculate the plinth area of given drawing
(Units are in CMs)

Plinth Area = 4.90x3.40=16.66 Sqm

Plinth area
The following shall not be included in the plinth area
I. Area of loft.
II. Internal sanitary shafts more than 2 sq.m. in area.
III. Unenclosed balconies.
IV. Towers, turrets, domes etc. projecting above the terrace level
not forming a storey at the terrace level.
V. Architechtural bands, cornices etc.
VI. Sunshades, Vertical sun breakers or box louvers projecting
out.

External services
In a project besides the building structure, some outside work are required
which come under External services.
Eg:
 Digging, filling, levelling and dressing of road.
 Road including approach road,
 External sewerage, sewage, disposal of works.
 Exrternal electrical service line with posts,
 Plantation of trees.
 Storm water drains, fencing or compound wall, gate, etc.
The cost of external services works may vary from 10%
to 20% depending on the nature and size of the project.

Contingencies
The term ‘Contingencies; indicates incidental expenses of miscellaneous
character which can not be classified under any distinct item sub-head, yet
certain to the work as a whole.
In an estimate 3% to 5% of
estimate cost is taken as
contingencies

Work-charged establishment
During the construction of building or a project, a certain number of
work-supervisors are required to be employed. Their salaries and
infrastructure fund are paid from the amount of work-charged
establishment.
A percentage of 1.5 to 2% of
the estimated cost is included
in the estimated.

Tools and plants (T&P)
For big work or project a certain percentage of the estimated cost is
provided in the estimate for the purchase or rent of tools and plants which
will be required for the execution of the work. Normally the contractor has
to arrange and use his own tools and plants.
A percentage of 1 to 1.5 % of the
estimated cost is included in the
estimated.

Centage charges (Departmental charges)
When the engineering department takes up the work of other
department a certain amount of the estimated cost is charged to meet the
expenses of the establishment, designing, planning, supervision, etc.,
This percentage charge is known as centage charge. The centage charge is
provided in the estimate of the work of Central Government is undertaken
of execution. These charges also known as supervision charges for works.
A percentage of 10 to 15 % of the
estimated cost is included in the
estimated.

Schedule of Rates
A list of rates of various items of works in the form of a printed
books known as “schedule of rate books.”
It is used for preparation of estimates, serve as a guide in setting rates in
connection with contract agreement, and Project management.
Now
Delhi Schedule of Rates (DSR)
are widely used all over India

ARUN RAVI.K.R
Instructor, Draughtsman (Civil)
arunravikr@gmail.com
9447622946

Estimating part 1

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