2. Approximate estimate is prepared to decide
the financial aspect, administrative approval
for sending the proposal and appraisal of
various civil engineering works.
The approximate estimate is prepared from
the practical knowledge and cost of similar
works.The estimate is accompanied by a
report duly explaining necessity and utility of
the project and with a site or layout plan.
3. To give a rough idea of the probable expenditure: At the early
stages of the development of a project it is necessary to ensure
whether the project can be financed. A rough idea of the probable
expenditure has to be obtained and if this appears feasible, then
further details may be considered.
Administrative approval: In the case of government and other
public works, proper sanction has to be obtained for allocating the
expenditure required for the detailed investigations and
preparation of plans and estimates.This sanction is given based on
approximate cost estimating method.
Valuation and rent fixation: Sometimes it is required to estimate
the cost of an existing structure, for one or more of the following
reasons: for sale or purchase, for rent fixing, for framing tax
schedules, or for insurance requirement. In these cases the
approximate methods are adopted.
4. Service unit method
Plinth area rate method
Cubical content method
Typical bay method
Approximate quantity method
5. Buildings are constructed to serve a specific purpose.
For example hospitals are designed to accommodate
certain number of beds. Each bed is then considered
a service unit. Hotels are designed to accommodate
certain number of guest rooms. each guest room is
considered a service unit. Same applies to offices,
residential houses, .. etc.
Whenever a building is constructed the Engineer or the
architect keeps the record of the place, actual cost,
number of service units, and the year of construction.
From this record, it is possible to work out the cost per
service unit.
Approximate Estimate can be calculated by
multiplying no. of service unit and Rate of per service unit.
6. In this methodThe built up area of the
proposed structure is worked out, and then
multiplied by a suitable rate.
This rate of construction per square meter
of built up area is worked out by dividing the
known cost of construction of a similar
building by the built up of that building.
App. Estimate = Built up area of proposed
structure X Rate per Sq m of built up area
7. This method is more accurate than the
square meter of floor area method. because
the depth of foundations and the height of
the structure above the ground level are the
additional dimensions taken into
consideration.
App. Estimate = volume of buildings x
rate/ unit volume.
The calculation of Sub structure and super
structure is done separately
8. This bay method is applicable in garages,
factory, and railway platform where identical
structures are visible.
Bay in a construction term means a
compartment of a building Or Space between
two supports in building.
The cost of one bay is calculated first and it is
multiplied by the number of bays.
App. Estimate = No. of Bays X Rate per Bay
9. For estimate of a railway project main
work are foundation embankment in cutting
and banking, bridges, culverts, level, and road
crossing, fencing etc are prepared by
knowing the cost per Km of recently
constructed similar structure.
App. Estimate = length of structure in Km X
Rate per Km
