Unit I & II
Estimating and Costing
Def: The process of
determination of quantities of items of work and its cost for completion
1.
Construction Activities
a.
Plans
i.
Plans
ii.
Elevations
iii.
Sections
b.
Estimating and Costing
i.
To calculate the quantities of various items of
work
ii.
To calculate the cost of structure
c.
Execution (Construction)
2.
Requirements to prepare an estimate
a.
Drawings
b.
Specifications
i.
Properties of materials
ii.
Mix Proportions
iii.
Workmanship
iv.
Source of materials and Conveyance
c.
Rates
i.
Standard Schedule of Rates (SSR) – approved by
the concerned engineering authorities every year
ii.
Local market rates for the items which are not
covered in SSR
iii.
Rate per unit work of various items of work can
be worked out by the Method of Analysis or Analysis of Rates using
1.
Standard Data
2.
Lead Rates from SSR
3.
Types of Estimates
a.
Approximate Estimate or Rough Estimate as per
Practical Experience
b.
Detailed Estimate as per Drawings
S No
|
Description of work
|
No’s
|
L
|
B
|
D/H
|
Quantity
|
Total Quantity
|
c.
Abstract Estimate – it gives accurate cost of
the project
S No
|
Description of work
|
Quantity
|
Rate
|
Per
|
Amount
|
Remarks
|
4.
Accuracy in Estimation
a.
All measurements shall be measured to the
nearest 0.01m
b.
All the areas shall be worked out the nearest
0.01 Sq.m
c.
All the volumes shall be worked out the nearest
0.01 Cum
5.
Types of Specifications
a.
General Specification (Brief Specification)
b.
Detailed Specification
6.
Lump sum Items which are not possible to workout
in details
a.
Electrification @ 8 to 10%
b.
Water supply and Sanitary works @ 8 to 10%
c.
Contingencies and unforeseen items
7.
P S Charges @ 2.5% – Salaries of Supervisors
(Temporary Staff)
a.
Works Inspector
b.
Work Assistants
c.
Technical Masteries
d.
Watchmen etc.,
8.
Units of Measurement of various items of work
9.
Main Items of work (Buildings)
a.
Earthwork Excavation
i.
All types of soils except rock
ii.
Rock cutting
iii.
Pipeline trench
iv.
Road Formations
1.
Cutting
2.
Embankment
b.
Refilling of Foundations
c.
Concrete Foundations
i.
Plain Cement Concrete (PCC 1:4:8 or 1:5:10)
using 40mm HB Metal
ii.
Reinforced Cement Concrete (RCC)
1.
Footings
2.
Foundations
d.
Masonry
i.
Stone Masonry for Foundation
ii.
Brick Masonry for Superstructure and Parapet
Walls
e.
RCC works
i.
Columns
ii.
Plinth Beam
iii.
Lintels and Sunshade
iv.
Roof Beams
v.
Roof Slab
vi.
Staircase & Lifts
f.
Flooring
i.
Cement Flooring
ii.
Cuddapah Slabs
iii.
Marble
iv.
Granite
v.
Vitreous Tiles
g.
Roofing
i.
RCC Slab
ii.
AC Sheet
iii.
GI Sheet
iv.
PVC Roofing
h.
Plastering for
i.
Concrete works – 12mm thick
ii.
Stone Masonry – 20mm thick
iii.
Brick Masonry – 12mm thick
i.
Pointing for Stone Masonry
j.
Doors (1.0 x 2.0m) and Windows (0.9 x 1.2m)
k.
White Washing, Color Washing and Distempering
l.
Painting – Coefficients for
i.
Door Paneled – 2.25 times
ii.
Window Paneled – 2.75 times
iii.
Cup Board – 2.25 times
iv.
Glazed Door or Window – 1 time
v.
Flush Door – 2 times
m.
Steel Reinforcement for
i.
Lintels @ 120 kg/cum
ii.
Sunshade @ 10 kg/Rmt
iii.
Roof Columns @ 160 kg/Cum
iv.
Roof Beams @ 160 kg/Cum
v.
Roof Slab @ 80 kg/Cum
10.
Methods of Taking out Quantities
a.
Center line method
b.
Long wall Short wall method
