Estimating and Costing

Updated: May 15, 2020

Estimating and costing

Quantity survey- it means that calculation of quantity of required to complete the word concerned

specification- detailed specification give the nature, quality and class of work materials to be used in the various part of work quality of the material their proportions,workmanship And description of of execution of work.

site plan- it is a plan Drone for a particular construction showing its position with respect to approaching roads, main market and other permanent features in populated area

Some important term

1. plinth area- the built up cover area office building measured at floor level of any storey is called plinth Area.

wall area, porch, internal shaft (2m²), duct lift, staircase room, machine room etc. are included cantilever porch, external staircase, Terrance at first floor, additional floor for sitting In assembly building, theatres auditorium.

2. carpet area- the covered area usable space of room of any floor it is measured between wall-to-wall Ribbon building.


following area not include in carpet area.

1. wall area

2. Veranda

3. corridor and passage

4. entrance hall and porch

5. staircase and stair cover

6. lift shaft and machine room for lift

7. bathroom and lavatory

8.Kitchen and pantry

9. Store

10. Canteen

11. air conditioning duct and plant room

12. internal shaft hor sanitary piping


3. Floor area- plinth area - wall area


4. Setback area- setback area can be explained as the minimum open space required around any building or structure

Municipal regulations make it mandatory for a specific distance to be maintained between a building is being constructed on, in order to keep it away from road water bodies and other buildings.



5. circulation area- area that is helpful in movement of people through, arround and between buildings and other parts of the built environment.

lobbies, corridor , stair, lift, landing etc.


What is floor area ratio (FAR)

the area ratio is the relationship between total amount of usable floor area that of building has or has been permitted to you have and the total area of the the plot on which the building stands the ratio is is determined by dividing the total or gross floor area of the building by ghost food area of the plot.

Floor area ratio= (total building floor area/ gross plot area)


1. what is the floor area ratio for single storey building with plot area 1000 square metre floor area 500 square metre ?

Floor area ratio=500/1000 =0.5


2.Floor area ratio (FAR) horse food storey building with plot area 4000 square metre and floor area 500 square metre?

Floor area ratio=(500X4)/4000 =0.5


Estimation

Estimating is the technique of calculating for computing the various quantities and the expected expenditure to be incurred on a particular work or project

In case the fund available are less than the estimated cost, act the work is done in part or by reducing it or by the alternate specification, the following requirements are are necessary for preparing estimate

>> drawing like plan, elevation and section of important point

>> detailed specification about the workmanship & properties of Material

>> Standard 6 dual of rate of the current year.


Need of estimation

estimate give an idea of of the cost of the work feasibility can be e determined i.e whether the project would be taken of week the funds available or not

estimate gives an idea of time time required for the compilation of work.

Estimate is required to invite the tender and quotation and to arrange contract.

estimate is also required to control the the the expenditure during the execution of work.

decide weather the proposed plan message the fund available or not

Prosedure/ method of estimate

estimate involves the following operation

1. preparing detailed estimate

2. calculating the rate of of each unit of work.

3. preparing abstract of estimate


Data required for preparing estimate

1. drawing- if the drawing are not clear without complete dimension the preparation of estimate become very difficult. so it is very essential data required for estimate.

2. specification-

a) general specification- this gives the nature quality, class and work and material in general terms be used in various part of work it helps to form a general idea of building.

b) detailed specification- please give detailed description of the the various items of works laying down the quantities and qualities of materials, there proportions the method of preparation, workmanship and execution of work.


c)Rate:- for preparing the estimate the unit rate of each item off work are required.

i) For arriving at the unit rate of each item.

ii) the date of various materials to be used in in the construction

iii) the cost of transport materials.

iv) the wages of labour, skilled or unskilled mason, carpenter, majdur etc.


Complete estimate

a) cost of land- Actual cost of land, cost of serving, cost of verification of deed and execution deed ,Brokerage if any.

b) contingencies

c) legal expenses between owner and contractor

d) cost of construction - cost of labour, cost of material, Consulting Engineers.



work charged establishment

during the construction of a project considerable number of of a skilled supervisors, work, assistance, watchmen etc are employed on temporary basis.

the salaries of this person are are drawn from lump sum amount allotted towards the work charged establishment. which is charge directly to work .A lump sum amount is is 1.5 to 2% of the estimated cost is provided towards the work charged establishment


lump sum

while preparing an estimate it is not possible to work out detail in case of petty items, items other than civil engineer search items is lump sum item

the following are sum of lump sum item in the estimate

i) water supply and sanitary arrangements(8%)

ii) electrical installation

iii) architectural features

iv) contingency and unforeseen item (3-5%)

v)Work charged establishment



In general certain percentage on the cost of estimation is allotted for the above lump sum item Even if sub estimate prepared or at the end of a execution of work, the actual cost should not exceed the lump sum amount provided in the main estimate.


Measurement of materials and works

the limit of measurement are mainly categorised for their nature shape and size and for making payment to the contractor and also show the principal units of measurement normally consists of the following.


a) single units work like doors, Windows, trusses etc. are expressed in number.

b) what's consists of linear measurements in length like cornice, fencing, handrail, band of specified with etc. are expressed in running metre.

c) what consists of areal surface measurement in area like plastering, white washing, partitions of specified thickness etc are expressed in square metre.

d) work consist cubical contains with involve volume like earth work, cement, concrete,

Masoenary etc are expressed in cubic metre.



important item of work

Earth work- it is measured in in m³ but payment is done in in 100 m³

in foundation we use lean concrete or weak concrete.

general thickness of concrete is 20 to 45 cm

Soiling- when the soil is soft/ bad then one layer of dry weak stone is applied below the concrete paste. this process is called soiling


DPC- damp proofing course

thickness varies from 2 to 2.5 cm rich cement mortar M20 (i.e- 1:1.5:3)


Pointing and plastering

thickness of plastering is 12mm

Plastering and Pointing is in metre square

following are the deduction condition for opening

no deduction made for small area 0.5m²

0.5- 3m² For opening area, then one side deduction

for opening area greater than 3m² then deduction is made both side.