Estimation is the technique of calculating or computing the various quantities and expected expenditures to be incurred on a particular work or project.

1. ESTIMATION
(ARCH 683)
- LIPIKA PANDEY
6TH SEM, B.ARCH

2. CONTENTS
o Introduction
o Need for an Estimate
o Procedure of Estimation
o Data required to prepare an Estimate
o Types Of Estimate
o Methods to Calculate Estimate
o Example
o Estimation for a Small Room

3. INTRODUCTION
Estimation is the technique of calculating or computing the various quantities and expected
expenditure to be incurred on a particular work or project.
NEED FOR AN ESTIMATE –
o To know about the estimate cost of the project.
o To calculate the tax of the building.
o To fix the rent of the building.
o To know the cost of the various materials involved in construction.
o To arrange the labours for the project.
o To take approvals for the government projects.
o To have loan from bank.
o To understand the time required for project completion.

4. INTRODUCTION
PROCEDURE OF ESTIMATION –
o Preparing detailed estimate.
o Calculating the rate of each unit of work.
o Preparing abstract of estimate.
DATA REQUIRED TO PREPARE AN ESTIMATE–
o Drawings and detailed contents.
o Materials specifications and rates.
o Labour requirements.
o Accessibility to plot.
o Transportation cost.
o Purpose of building.
o Site location.

5. TYPES OF ESTIMATE
TYPES OF ESTIMATE–
o Abstract or Approximate or Preliminary Estimate – It is the estimate prepared using
any rough method to get an approximate cost of the project.
o Rough cost estimate based on Plinth Area – It is the estimate prepared on the basis
of plinth area of the various buildings proposed to be constructed.
o Rough cost estimate based on Cubic Content – It is the estimate prepared on the
basis of cubic content (plinth area x height of building) of the various buildings
proposed to be constructed.
o Detailed Estimate – It is the estimate which provide the item wise quantities of work,
item wise unit rate, and item wise expenditure in the project.

6. TYPES OF ESTIMATE
TYPES OF ESTIMATE–
o Annual Repair Estimate – It is prepared by the concerned department for getting
allocation of funds made in the annual budgets.
o Special Repair Estimate – It is prepared when the work cannot be carried out of the
annual repair funds due to certain reasons resulting in genuine increase in the cost.
o Revised Estimate – It is prepared when, the sanctioned estimate exceeds 5% either
due to the rate being found insufficient or due to some other reasons.
o Supplementary Estimate – This is fresh detailed estimate in addition to the original
sanctioned estimate prepared when additional works are deemed necessary during
progress of work to supplement the original works.
o Complete Estimate – It includes, additional cost of construction, land, surveys, legal
assistance, registration documents, taxes, services, plans, etc.

7. METHODS TO CALCULATE ESTIMATE
METHODS TO CALCULATE ESTIMATE–
o Centre Line Method – In this method total centre line length of walls in a building is
calculated and then multiplied by the breadth and the depth of the respective items
get the total quantity. Centre line method is applicable to the square building with
symmetrical offsets. It is more accurate and fast method as compared to other
methods.
o Crossing Method – It is designed for calculating materials needed for masonry walls.
In this method, the lengths and breadths of walls at plinth level (the base on which a
column is raised) are included. The internal dimension of the room and the thickness
of the walls are also important to calculate the quantities. Symmetrical offsets should
be counted as they play a major role in the calculation of quantity of materials.

8. METHODS TO CALCULATE ESTIMATE
METHODS TO CALCULATE ESTIMATE–
o Out to Out, and In to In Method – This method follows P
.W.D system for computing
materials and this seems to be the most accurate method among all.
o Bay Method – It is applicable in garages, factory, and railway platform where identical
structures are visible. Bay in a construction term means a compartment of a building.
The cost of one room is calculated first and it is multiplied by the number of bays.
o Service Unit Method – The term service unit method is designed for building with
identical rooms. This method is applicable in the construction of college, hospital,
cinemas, prison, and more. When it is a construction of a hospital, the service unit will
be a bed. Likewise, for cinema/stadium, it is seats.

9. EXAMPLE
ESTIMATION FOR A SMALL FULLY FURNISHED ROOM–
o Room Size – 10’ x 10’
o Foundation/ Footing Cost – Let Foundation size is 4’×4′ and 4’ depth, so volume of
soil excavation for 4 footing = 4× 4’×4’×4′ = 256 cubic feet. Converting into cubic
meter 256/35.32 =7.25m³. Soil excavation rate is around Rs. 800 per m³ for hard soil
and Rs. 300 per m³ for soft soil. We take soil excavation rate Rs. 400/m³ for this
calculation. Total cost of soil excavation for foundation = 7.25 × 400 = Rs. 2900.
o Brick work quantity and Cost calculation – Assume that the room 10’×10′ have 9″
brick wall on four side height up to 10’ and parapet wall for partition wall will be of
inch. Outer dimension of room is 11.5’×11.5′ and inner dimension of room excluding
brick wall is 10’×10′.
Area of one brick wall =10’×10′ =100 sq foot
Area of 4 brick wall =4 ×100 = 400 sq foot.

10. EXAMPLE
ESTIMATION FOR A SMALL FULLY FURNISHED ROOM–
Door size = 4’×7′ = 28 sq ft.
Window size = 3’×4’= 12 sq ft.
Door and window size should be deducted from total area of brick wall.
Net area of brick wall= 400 - (28+12)= 360 sq ft
Volume of 9 inch thick brick wall = 360×9/12 = 270 cubic feet, converting into
cubic meter we have 270/35.32=7.65 cubic meter.
Consider parapet brick wall 3.5 feet height 4.5 inch thick, and outer dimension of
room is 11.5’×11.5′ = 132.25 sq ft, total area of parapet brick wall on all four side =
11.5 × 3.5 ×4 =161 sq ft.
Volume of parapet wall =( 4.5/12)×161=60 cubic ft, converting into cubic meter,
60/35.32 = 1.70 cubic meter.
Total brickwork = 4 brick wall + parapet wall = 7.65+ 1.70 = 9.35 cubic meter.
We know, for 1 cubic meter of brickwork we require 500 bricks, 1.26 bags of
cement and 9.28 cubic feet sand quantity.

11. EXAMPLE
ESTIMATION FOR A SMALL FULLY FURNISHED ROOM–
o Brick work quantity and Cost calculation – Number of brick in 9.35 cubic meter =
500×9.35= 4675 no's, suppose first class brick rate is around Rs. 8000 per thousand,
brick cost = 8000× (4675/1000) = Rs. 37400.
o Cement quantity and their Cost – Quantity of cement required for 9.35 cubic meter
brickwork is 1.26 × 9.35 = around 12 bags cement. Suppose market rate of cement is
around rupees 400 per bag so cement cost = 12×400= Rs. 4800.
o Sand quantity and their Cost – Quantity of sand required for 9.35 cubic meter brick
work is 9.28 × 9.35 = 87 cubic ft. Market rate of sand is around Rs, 40 per CFT then
sand cost= 87 ×40 = Rs. 3480. So total brickwork cost = brick cost + cement cost +
sand cost = 37400 + 4800 + 3480 = Rs. 45680.

12. EXAMPLE
ESTIMATION FOR A SMALL FULLY FURNISHED ROOM–
o Concrete quantity and Cost calculation for Footing, Column, Plinth Beam, Wall Beam and
RCC Slab – Footing is 4 feet depth and column size is 9 inch into 12 inch and height of
column is 10 feet up to slab and 3.5 feet above slab. There is four column. So column
length is = 4’+10’+3.5’= 17.5′. Total volume of concrete quantity for 4 column = 4 ×
(9″×12″)×17.5′ = 4 × 13.125 =52.5 cubic feet.
Plinth beam size 9″×12″ for all around for length 11.5×4 = 46 feet. Total volume of
concrete quantity for plinth beam = (9″×12″)× 46 = 34.5 cubic feet.
Wall beam size 9″×9″ for all around for length 11.5×4 = 46 feet. Total volume of
concrete quantity for wall beam = (9″×9″)× 46′ = 25.9 cubic feet.
RCC slab 5 inch thick for 11.5’×11.5′, concrete volume is 11.5’×11.5’×5/12′ = 55 cft.
Total Weight volume of rcc concrete = concrete quantity for column + concrete
quantity for RCC plinth beam + concrete quantity for RCC wall + concrete
RCC slab = 52.5 +34.5+25.9+55 = 170 cft.

13. EXAMPLE
ESTIMATION FOR A SMALL FULLY FURNISHED ROOM–
Converting 170cft into cubic metre,170/35.32 = 4.8 m³. Ready mix concrete
available in market is around rupees 4000 per m³ for M20 grade of concrete, so
material cost of concrete = 4000×4.8 = Rs. 19200.
o Reinforcement Cost and Quantity Calculation – Suppose reinforcement required is 1% of
concrete volume for RCC work like footing column beam and RCC slab. Steel quantity =
(1/100)×4.8 m³ = 0.048 m³. Weight of steel = 0.048 m³ × 7850kg/ m³ = 376.8kg, market
rate of Steel is around 60 rupees per kg then total cost of Steel = 60×376.8 = Rs. 22600.

14. EXAMPLE
ESTIMATION FOR A SMALL FULLY FURNISHED ROOM–
o Labor Cost for Construction – Labor cost for construction of house around 180
rupees per square foot without plastering and PCC or tile flooring.
So total outer area of one room is 11.5’×11.5 = 132.25 square foot, total labor
cost = 180×132.25 = Rs. 23805.
o Therefore, Total Cost of Construction for a Small Room without PCC Plastering and
Floor Tiling = Soil excavation cost + Brick work cost + Concreting cost +
Reinforcement cost + Labor cost.
= 2900 + 45680 + 19200 + 22600 + 23805 = Rs. 114200 (approx.)

15. EXAMPLE
ESTIMATION FOR A SMALL FULLY FURNISHED ROOM–
o Now consider finishing cost is about 60% of total construction cost of one room,
finishing should be required plastering, PCC flooring, tile flooring, putty painting,
electrical fitting, lumbering, water and sanitization.
Therefore, 60% of construction cost of one room = (70/100)×114200= Rs. 68520.
Hence, the Total Cost =114200+68520 = Rs. 182700.

16. Thank You!