Types of estimates

TYPES OF ESTIMATES
Prepared by:-
Simarpreet Singh
A.P, Civil Engg.
ACET, Amritsar

 Contingencies – Indicates incidental expenses of
miscellaneous character which cannot be classified under any
distinct item. (3% to 5% of the estimated cost is provided to
allow for contingencies)
 Work-charged Establishment – Work-charged employees are
temporary staff whose services are terminated at the expiry
of sanctioned period but usually one month notice is given.
(1.5% to 2% of the estimated cost is added)
 Tools and Plants – Normally contractor has to arrange tools
and plants. (1% to 1.5% of estimated cost is provided)
 Centage charges or Departmental charges – Also known as
Supervision charges for works. To meet the expenses of
establishment, designing, planning, supervision etc. (10% to
15% of the estimated cost). When engineering department
takes up work of other department.
TERMINOLOGY

 Report gives brief information of whole project. It should consist of the
following :
 Brief history (with proposal)
 Necessity and feasibility of project
 Selection of site
 Survey
 Brief description of works
 Nature of soil, topography of land etc.
 Basis of design calculations
 Arrangement for water supply, sanitation and electrical installations etc.
 Roads and drains
 Temporary accommodations for staff, labour etc included in misc.
 Manner of execution
 Total cost and how to be financed
 Return or revenue income
 Rent statement
 Time of execution
TERMINOLOGY

 Sub-Head items of work – Works like earthwork, concrete
work, brick work etc. Under each sub head there are different
items of work.
 Sub-Work – Large project may consist of small buildings.
Detailed estimate of each sub-work is prepared separately.
 Schedule of Rates – It is a list of rate of various items of
works maintained by engineering department under the name
“Schedule of Rates Book”. “Road Metal Rate Book” is also
maintained by PWD.
 Administrative Sanction/ Approval – It is the formal
acceptance by the department concerned of the proposal.
After the approval, design, estimates etc. are prepared and
thereafter execution of work.
TERMINOLOGY

 Expenditure Sanction – It represents allotment of money to
meet the expenditure. It is usually accorded by Finance
Department.
 Technical Sanction – It is the sanction of the detailed
estimate, design calculation, quantities of work etc. Technical
sanction is accorded by engineering department and
execution of work is carried out thereafter.
 Quantity Survey – It means estimating of quantities of
different items of works.
 Plinth Area – It is the built up covered area of a building
measured at floor level of any storey by taking external
dimensions of the building at the floor level.
TERMINOLOGY

 Floor Area – It is obtained after deducting area of walls from the
plinth area of building. It should include:
 Door and other openings
 Intermediate pillars and supports
 Circulation Area – It is the floor area of verandahs, passages,
corridors, balconies, staircases, lift etc. which are used for
movements of persons using the building. It is further classified
into Horizontal and Vertical.
 Carpet Area – It is the useful area of the building. It is
determined after deducting :
 Circulation Area
 Sanitary Accommodations
 Kitchen, Pantry, Stores
 For office building approximate 60% to 75% of plinth area
 For residential buildings approximate 50% to 65% of plinth area
TERMINOLOGY

 Site Plan – Plan showing orientation of building, boundaries of
land, position of roads, drains, sewer line, water pipelines and
adjoining plots of lands. North direction is also shown on one
corner of site plan)
 Layout Plan –
 Plan showing proposed buildings, structures etc. showing their locations,
size and orientations.
 Roads, drains, pipe lines , electric lines, parks etc are shown.
 The boundary, main approach roads and adjoining areas are also
indicated.
 Index Plan –
 Plan is usually drawn for Roads, Irrigation, Water supply etc.
 It shows alignment with position of culverts, main outline of whole work
to give idea of the project
 For big project it is drawn with much small scale and is known as key
plan
TERMINOLOGY

 Preliminary/Appx./Abstract/Rough Cost Estimate
 Plinth Area Estimate
 Cube Rate or Cubical Content Estimate
 Appx. Quantity Method Estimate
 Detailed Estimate or Item Rate Estimate
 Revised Estimate
 Supplementary Estimate
 Supplementary and Revised Estimate
 Annual Repair or Maintenance Estimate (A.R or A.M
Estimate)
DIFFERENT TYPES OF ESTIMATES

Preliminary Estimate is prepared by various ways for different
structures as mentioned below :
 Buildings
 Per Unit Basis – Per student for schools and hostels, per class room
for schools, per bed for hospitals, per seat for cinema and theatre
halls, per tenement for residential buildings.
 Plinth area basis
 Cubic content basis
 Appx. Quantity method
 Roads and Highways – Per km basis depending upon nature of
road, width and thickness of metalling.
 Irrigation Channels
 Per km basis
 Per hectare basis (Area of land commanded)
PRELIMINARY ESTIMATE

 Bridges and Culverts – Per running meter of span depending
upon type of structure, type and depth of foundation.
 Sewerage and Water Supply Project
 Per head of population served
 Per hectare basis (Area covered)
 Over Head water Tank – Per liter or per gallon of tank
depending upon type of structure and height of tank.
PRELIMINARY ESTIMATE (Ctd.)

 P.A. is approximate estimate
 Plinth area should be calculated for covered area by taking
external dimensions of the building at the floor level
 Courtyard and other open area should not be included
 For multi storeyed building Plinth Area for each storey is
determined separately.
 Approximate total plinth area may be calculated by adding 30
to 40% of the already calculated area for walls, circulation
and waste etc.
 Plinth area rate is known from cost of similar building in the
locality.
PLINTH AREA ESTIMATE (P.A. ESTIMATE)

 Cube rate estimate is again approximate estimate
 Cubical content of the building is determined by multiplying
length, breadth and height of the building.
 External length and breadth at the floor level are calculated
for the purpose
 Height should be taken from the floor level to the top of roof.
 For multi storeyed building height is taken from floor level of
one storey to top of next higher floor.
 Cube rate estimate is more accurate as compared to the
plinth area estimate.
CUBE RATE ESTIMATE

 Structure divided into two parts – (i) Foundation including
plinth (ii) Superstructure
 Total length of walls is found out.
 To find running meter rate of foundation, appx. quantities of
various items are calculated per running meter
 Similarly for superstructure appx. Quantities of brickwork,
roof, flooring etc is calculated per running meter.
APPROXIMATE QUANTITY METHOD
ESTIMATE

 It is the accurate estimate prepared by working out quantities of
each items of work.
 It is prepared in two stages –
 Details of measurements and calculation of quantities.
 Abstract of estimated cost – 3% to 5% of estimated cost is added to
cover miscellaneous expenditure
 Detailed estimate is prepared work-wise.
 Detailed estimate consists of –
 Report
 General Specifications
 Detailed specifications
 Drawings
 Calculation and designs
 Analysis of rates
 Detailed estimate is prepared for technical sanction, for
arranging contract and for execution of project.
DETAILED ESTIMATE

 Revised estimate is prepared when original sanctioned
estimate is likely to exceed more than 5%.
 When expenditure on work is likely to exceed amount of
administrative sanction by more than 10%
 When there are material deviation from original proposal even
though cost may be met from sanctioned cost.
 It is accompanied by comparative statement showing
variations in each item of works and reason for the same.
REVISED ESTIMATE

 It is the fresh detailed estimate of the additional works in
addition to the original estimate.
 It is required when further development is required during the
progress of work.
 Abstract should show the amount of original estimate and
total amount including supplementary amount.
SUPPLEMENTARY ESTIMATE

 When a work is partially abandoned and estimated cost of
remaining work is less than 95% of original sanctioned
estimate.
 When there are material deviations and changes in the design
 If at any time before or during the execution of work, it is
found that original estimate is excessive then divisional
officer may sanction a revised estimate of reduced amount.
SUPPLEMENTARY AND REVISED
ESTIMATE

 It is prepared to maintain structure or work in proper order
and safe condition
 For buildings like white washing, painting, minor repairs etc.
 For road works A.R. estimate provides for patch repairing,
repairs of bridges and culverts etc.
ANNUAL REPAIR OR MAINTENANCE
ESTIMATE (A.R / A.M ESTIMATE)

Types of estimates

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