Estimating Costs and Material Requirements for Your Home
 Guide of Home Construction Material and Cost Estimation  How do you estimate
the materials needed to build a house?
It is always worthwhile to estimate the cost of the proposed construction so that it does not exceed the available finances. We have already seen in the article “Classification of Buildings” how a building can be classified as class I, II or III. If the approximate cost to build a building of a particular class in a given locality is known the total cost of the building, can be estimated on an area basis. In this article, we will examine the various components of the cost of the building so that we can control the cost during the execution stage itself. Charges for supervision and the supply of labour and materials which are paid for by the owner are usually taken as 7 to 10% of the overall cost of the building. In lump sum and itemwise contracts, because of the new tax laws, contractors expect a profit of 15 to 20% of the cost of the work.
BREAK UP OF COST OF
CONSTRUCTION
The table below gives the approximate average
percentage cost of civil works for a residential building. It also
indicates the possible savings that can be made. The actual values will depend
on many factors like foundation condition and architectural features.
Table: Percentage cost of civil works
S.No. 
Works 
Cost (% of the total
cost) 
Possible savings (% of the total
cost) 
1. 
Foundation and plinth 
10 to 15 
1 to 3 
2. 
Superstructure 



(wall + roof, including plastering) 
30 to 40 
4 to 13 
3. 
Painting 
5 to 20 
1 to 8 
4. 
Doors and windows 
12 to 20 
1 to 8 
5. 
Flooring 
10 to 20 
2 to 7 
In
addition, the cost of services is usually estimated as a percentage of civil
works and is taken as follows:
Water supply and sanitation 
10 to 12.5 per cent 
Electrical works 
8 to 12.5 per cent 
External works 
2 to 5 per cent 
Total 
20 to 30.0 per
cent (max) 
RATIO OF COST OF
MATERIALS TO LABOUR
It
has been found that the total cost can be divided
into the following percentages for
an ordinary building built in India in the traditional way:
1. Material cost  60 per cent of the
total cost
2. Labour cost  30 per cent of the
total cost
3. Other costs  10 per cent of the
total cost
The
break up of the cost of materials can be approximated as given in the Tables below
Cost of principal materials
S.no 
Item 
Approximate cost
as % cost of the civil work 
1. 
Bricks 
15 to 18 
2. 
Cement 
12 to 18 
3. 
Steel 
5 to 15 
4. 
Timber 
10 to 15 
5. 
Sand 
7 to 10 
6. 
Aggregate 
8 to 10 
7. 
Paint 
5 to 10 
Cost of labour
S.no 
Worker 
Approximate cost
as % of civil works 
1. 
Mason 
12 
2. 
Unskilled labour 
12 
3. 
Carpenter 
6 
CONSUMPTION OF MATERIALS
FOR BUILDINGS
The
data given in the Table below can be taken as very approximate quantities of materials required for construction of an ordinary
building.
Table: Very approximate quantities of
materials required for a 1 m^{2} plinth area
S.No. 
Materials 
Quantity per m^{2}
of plinth area 
1. 
Bricks
(9" ordinary) 
250300
nos. 
2. 
Sand 
0.5
to 0.7 m^{3} 
3. 
40
mm aggregates 
0.2
m^{3} 
4. 
20
mm aggregates 
0.2
m^{3} 
5. 
Steel
for buildings with load bearing walls 
10
to 20 kg 
6. 
Steel
for framed flats and hostels 
30
to 50 kg 
7. 
Steel
for framed offices 
40
to 70 kg 
8. 
Cement
for load bearing walls 
3
bags 
9. 
Cement
for framed buildings 
4
bags 
10. 
Lime
for brick jelly 
40
litres 
ANALYSIS OF ITEMS OF
WORKS
The
quantities of important items of work
for buildings can be worked out to control cost as shown in the Table below
which is for a middleclass building
on load bearing walls. The values shown are not exact but only indicative.
Table: Items of works for residential buildings on
loadbearing walls (Quantitative are only indicative. Actuals will depend on
the design.)
s.no 
Materials 
Approximate
quantity per m^{2 }of the plinth area 

G.F ONLY 
G.F + F.F 

1 
Earthwork 
0.52 m^{3} 
0.30 m^{3} 
2 
Mass concrete in foundation and under
floor 
0.22 m^{3} 
0.15 m^{3} 
3 
RCC in foundation 
0.11 m^{3} 
0.06 m^{3} 
4 
Brickwork in foundation (varies) 
0.16 m^{3} 
0.09 m^{3} 
5 
Brickwork in superstructure 
0.40 m^{3} 
0.40 m^{3} 
6 
RCC in superstructure: 


Plinth/lintel/beam 
0.05 m^{3} 
0.05 m^{3} 

Slab and stairs 
0.01 m^{3} 
0.18 m^{3} 

Sunshade/shelves 
0.18 m^{3} 
0.01 m^{3} 

7 
Doors and windows 
0.45 m^{3} 
0.45 m^{3} 
8 
Plaster 
2.60 m^{3} 
2.60 m^{3} 
9 
Painting of walls and ceiling 
3.5 m^{3} 
3.5 m^{3} 
10 
Waterproofing 
0.98 m^{3} 
0.60 m^{3} 
11 
Flooring 
0.75 m^{3} 
0.75 m^{3} 
CEMENT REQUIREMENTS IN
CEMENT WORKS
Cement
is an important material and its consumption must be controlled. Some of
the data used for the calculation of cement requirements in concrete, mortar and
plaster are given in the Tables below
Table: Cement consumption for concrete
Mix 
W/c ratio 
Strength 
Cement per (m^{3
}of concrete (kg) 

With control 
Without control 

1 :1.5: 3 
0.42 
20 
30 
405 
1 : 2 : 4 
0.55 
15 
25 
310 
1 : 3 : 6 
0.75 
10 
15 
215 
1 : 4 : 8 
Used only for base concrete, etc. 
160 

1 : 5 : 10 
Used only for base concrete, etc. 
130 
Note:
1 cubic metre = 35.315 cubic feet; Approximate yield = 2/3 x Volume of mix.
Hence, volume of cement required per m3 of concrete is taken as (1.52/ Volume of mix) (approx).
Table: Requirements for 1 m^{3}
of cement mortar
Mix of mortar 
Cement (bags) 
Sand (m^{3}) 
1:3 
2.6 
0.267 
1:4 
1.9 
0.275 
1:6 
1.4 
0.299 
1:8 
1.1 
0.308 
Note:
For brick masonry, we need 500 metric
bricks (and 520 ordinary bricks) per cubic metre of brickwork and 25 to 30% of the volume of brickwork
will be taken up by a mortar. Hence, we need about 0.25 to 0.30 cft of mortar. One bag of cement is considered as 50
kg in weight and 35 litres in volume.
Table: Requirements for 100 m^{2}
of 12 mm thick cement plaster
Mix 
Cement
(bags) 
Sand
(m^{3}) 
1 : 2 
21 
1.4 
1 : 3 
15 
1.5 
1 : 4 
12 
1.6 
1 : 6 
9 
1.8 
Note:
1 square metre = 10.764 square feet
ESTIMATION OF STEEL IN RC
WORKS
For preliminary estimation, it is usual to assume the steel requirement on a percentage basis (or kg/m^{3})
of the easily calculable volume of concrete based on the data given in Table below.
The actual requirement by proper design will be much less.
(Note: Steel rods usually come in
lengths of 11 m. Hence we can check the weight of a consignment by counting the
rods. For example, the weight of a consignment consisting of 8 rods each of length 11 m = 11 x 0.395 =
4.4 kg, approximately.)
Table: Estimation of steel in buildings
components (Fe 415 steel)
Item 
Coefficients
for estimation of steel 

As
% of steel 
As
Kg/m^{3} 

Footings 
0.25 to 0.65 
20 to 50 
Cast Insitu Piles 
0.40 to 0.75 
30 to 60 
Rafts 
0.75 to 1.50 
60 to 120 
Columns 
1.00 to 4.0 
80 to 320 
Beams 
0.5 to 1.5 
30 to 100 
Slabs and lintels 
0.3 to 0.6 
25 to 50 
Sunshades 
0.3 to 0.5 
25 to 30 
Note:
1% steel = 78.5 (say 80 kg) of steel per cubic metre of concrete.
Example: Find the steel required for a slab 15 x 10 m and 120 mm
thick.
Volume of concrete = 15 x 10 x 0.12 = 18 m^{3}
Assume % of steel is 0.4 % = (or 0.4 x 78.5 = 31 kg/m3)
Wt of steel = 18 x 31 = 565 kg
(Note: This works out to 565 ÷ 150 =
3.76 kg/m2 for slab only. In addition we have foundation beams, columns etc. so
that the total quantity will workout to 10 to 20 kg/m2)
TYPICAL MINIMUM
CONSUMPTION
The
minimum consumption of steel in kg/m^{2}
by proper design and detailing for a typical four storey building on good
soil using to Fe 415 steel can be a
total of 20 kg/m^{2}^{ }as
follows
Minimum steel for a fourstorey flat
ITEM 
STEEL
CONSUMPTION 
Foundation 
2.0 kg/m^{2} 
Plinth beam 
2.0 kg/m^{2} 
Columns 
4.0 kg/m^{2} 
Beams 
5.0 kg/m^{2} 
Slabs and stairs 
5.5 kg/m^{2} 
Lintels, sunshade etc. 
1.5 kg/m^{2} 
ANALYSIS OF RATES
One
of the topics studied in "estimating"
is the analysis of the rates of various items of works. The data for the cost of
materials, labour and other items such as scaffolding required per unit of work
for each item of work in each region of the country is available. From these
data, the cost per unit of work can be estimated. As it is a subject to be studied underestimating, we will not go into
a detailed study of the subject in this article.
ESTIMATION OF PAINT
REQUIRED FOR PAINTING AN AVERAGE RESIDENTIAL BUILDING
(a) Rough estimate of areas to be
painted in terms of plinth area: Area of ceiling = Floor area (say plinth area)
Area
of internal walls = 3 x plinth area
Area
of external walls = 2 x plinth area
Area
of windows = 30% plinth area on each side
Area
of doors = 30% plinth area each side
(b) Approximate coverage of different
types of paints per coat (Second and third coats will have 25% more coverage).
1.
Fat lime for limewashing 10 m^{2}/kg
(For
colour wash add 1 to 2 kg colour per 100 m^{2})
2.
Dry distemper 10 m^{2}/kg
3.
Cement paint 5 m^{2}/kg
4.
Cement wall primer 8 m^{2}/L (litre)
5.
Oil bound distemper 8 m^{2}/kg
6.
Plastic emulsion paint 10 m^{2}/L
7.
Acrylic exterior paint 12 m^{2}/L
8.
Metal primer 10 m^{2}/L
9.
Synthetic caramel paint 10 m^{2}/L
10.
Copal varnish for wood 10 m^{2}/L
MUST READ: Cost
Percentage Of Building Materials For 1000 Sqft of House Construction
MUST READ: Material
and labour Cost of One Room Construction  Room Estimation
FAQ
How Much Paint do I Need?
Example: Find the approximate quantity of paint required for
painting 200 m^{2} of wall with plastic emulsion paint in two coats.
Paint
required for first coat = (200/10) = 20.0 litres
Paint
required for second coat = 16.0 litres (10% less)
Total
= 36.0 litres (approx)
Note:
Generally one painter can be assumed to paint 1520 m^{2} of wall
surface per day, depending on the type of paint and finish.
How much paint do I need for one coat?
Approximate coverage of different types
of paints per coat (Second and third coats will have 25% more coverage).
1.
Fat lime for limewashing 10 m^{2}/kg
(For
colour wash add 1 to 2 kg colour per 100 m^{2})
2.
Dry distemper 10 m^{2}/kg
3.
Cement paint 5 m^{2}/kg
4.
Cement wall primer 8 m^{2}/L (litre)
5.
Oil bound distemper 8 m^{2}/kg
6.
Plastic emulsion paint 10 m^{2}/L
7.
Acrylic exterior paint 12 m^{2}/L
8.
Metal primer 10 m^{2}/L
9.
Synthetic cramel paint 10 m^{2}/L
10.
Copal varnish for wood 10 m^{2}/L
What is rate analysis?
One of the topics studied
in "estimating" is the analysis of the rates of various items of works.
The data for the cost of materials, labour and other items such as scaffolding
required per unit of work for each item of work in each region of the country
is available. From these data, the cost per unit of work can be estimated.
How many cement bags are used for
plastering?
Requirements for 100 m^{2} of
12 mm thick cement plaster
Mix 
Cement
(bags) 
Sand
(m^{3}) 
1 : 2 
21 
1.4 
1 : 3 
15 
1.5 
1 : 4 
12 
1.6 
1 : 6 
9 
1.8 
Note:
1 square metre = 10.764 square feet
What is the percentage of cost of
materials and Labour?
1. Material cost  60 per
cent of the total cost
2. Labour cost  30 per
cent of the total cost
3. Other costs  10 per
cent of the total cost
How much steel is in a building?
Estimation of steel in buildings
components (Fe 415 steel)
Item 
Coefficients
for estimation of steel 

As
% of steel 
As
Kg/m^{3} 

Footings 
0.25 to 0.65 
20 to 50 
Cast Insitu Piles 
0.40 to 0.75 
30 to 60 
Rafts 
0.75 to 1.50 
60 to 120 
Columns 
1.00 to 4.0 
80 to 320 
Beams 
0.5 to 1.5 
30 to 100 
Slabs and lintels 
0.3 to 0.6 
25 to 50 
Sunshades 
0.3 to 0.5 
25 to 30 
How to Calculate Construction Cost per Square Feet?
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