Thumb Rules In Building Construction For Civil Engineers | Important Point Of Civil Engineering | Construction Thumb rules

The thumb rule in civil engineering is used for quick decision-making and approximate estimates. Site engineers and supervisor are greatly benefited from thumb rules to arrive at a quick decision.

Every civil engineer or site supervisor shall have basic knowledge about certain civil engineering basics. The below-mentioned are must-have knowledge about civil engineering and practical knowledge. We will cover in-depth knowledge about the civil engineering field and practice.

This post will contain civil engineering tips and tricks That will be of immense importance to civil engineers.

We have shared an extensive list of thumb rules used in construction for various activities. If you get to benefit from it then please share.

Thumb Rules In Building Construction Cost

Thumb rule for construction cost estimates can speed up the rough estimation process. Based on thumb rules in civil engineering, one can have approximate cost and material and labour requirements as well.

The basic thumb rule for Building material requirements and building work per unit area is given below:

Sr. No.	Material/ Work	Thumb Rule
1.	Cement	0.5 Bags/sqft
2.	Steel	3 to 5 Kg/sqft
3.	RMC	0.05 m3/sqft
4.	Blockwork	12.5 no./m2
5.	Structural Civil Work	₹ 751.25/sqft
6.	Finishing Works	₹ 470/sqft
7.	Electrical Cost	₹ 133/sqft
8.	Plumbing Cost	₹ 126/sqft
9.	Fire Fighting Cost	₹ 40/sqft
10.	External Development Cost	₹ 94.5/sqft

Thumb rule for construction cost of building material percentage wise

Description	Thumb rule (% of Total Cost)
Cement	16.4%
Sand	12.3%
Aggregate	7.4%
Steel	24.6%
Painting material	4.1%
Tiles	8%
Bricks	4.4%
Window	3%
Doors	3.4%
Plumbing	5.5%
Electrical	6.8%
Sanitary	4.1%

Thumb rules for construction cost

The average cost of Construction based on the quality of construction is shown below.

Sr. No.	Construction based on Quality	Thumb Rule
1.	Basic Quality Construction	1100 Rs./Sqft
2.	Medium Quality Construction	1400 Rs./Sqft
3.	High Quality Construction	1800 Rs./Sqft

Thumb rule for average cost of construction for 1000 sqft house.

Sr. No.	Description of Work	Average Cost for 1000 sqft home
1.	Cost of Architect	Rs. 15,000 Onwards
2.	Brick wall without RCC	Rs. 800 per sqft
3.	Brick wall With RCC	Rs. 900 per sqft
4.	Civil Work	Rs. 1500 per sqft
5.	Electric and Plumbing	Rs. 2500 per sqft
6.	Raw Material Cost	Rs. 7 Lakh Onwards

Thumb rule for building cost is based on the whole project cost in terms of percentage.

Sr. No.	Work	Cost
1.	Excavation and Filling Earthwork	0.5%
2.	Foundation	5%
3.	Damp Proof Course	1%
4.	Brickwork	34%
5.	Roofing	20%
6.	Flooring	6%
7.	Doors and window	16%
8.	Plastering	10%
9.	White Washing	2%
10.	Miscellaneous	5.5%

Cost of building general thumb rules

Sr. No.	Work	Thumb Rule
	Cost of Material and Labour
1.	Material Cost	70% of Building Cost
2.	Labour Cost	30% of Building Cost
	Direct and Overhead Cost
1.	Direct Cost	85% building cost
2.	Overhead expense	15% of Building Cost
	Foundation and Superstructure
1.	Cost of Foundation	15% of Building Cost
2.	Cost of Superstructure	85% of Building Cost
	Electrical and Sanitary Work
1.	Plumbing and sanitation cost	8% of Building Cost
2.	Cost of Electrical Work	8% of Building Cost

Thumb Rule For Slab

• The minimum thickness of slab is 125mm.
• The minimum diameter of bars used in slab is 8mm.
• Fe 500 Steel should be used in the slab.
• Clear cover of 15mm to 20mm should be provided in slab.
• Maximum diameter of bars used in slab is 1/8^th times of slab thickness.
• Steel required in slab is 1% of the total volume of concrete.
• M15 Grade of concrete or above it should be used in slab.
• Spacing between reinforcement in slab should not be less than 150mm c/c.

Thumb Rule For Beam

• Steel required in beam is 2% of total volume of concrete.
• Minimum clear cover of 40mm shall be provided in beams.
• M20 grade of concrete should be used in beam construction.
• Minimum 4 bars shall be provided in beams. 2 bars of 12mm at top and 2 bars of 10mm at bottom.
• M15 Grade of concrete or above it should be used in slab.
• Spacing between reinforcement in slab should not be less then 150mm c/c.

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5. Steel Price Per Kg Today in India 2022

Thumb Rule For Column

• Steel required in Column is 2.5% of total volume of concrete.
• Minimum steel requirement in column = 0.8% of gross area of concrete
  Maximum steel requirement in column = 6% of the gross area of concrete
• Spacing between Longitudinal reinforcement should not be more than 300mm.
• Minimum clear cover in column is 40mm. 25mm clear cover is provided if column is less than 200mm.
• Minimum dia of 12mm bars 4 numbers should be used in column.
• The maximum diameter of reinforcing bars in column should be not more than 50mm.
• Overlapping distance in longitudinal bars should not be less than 24 times the smallest bar dia.
• Maximum spacing of stirrups is 16D or B or 300mm whichever is less.
• Minimum size of column should not less then 9″ X 9″.
• For G+1 Structure 9″ X 12″ (225mm X 300mm) Column should be used.
• Maximum space between two column of size 9″ X 9″ should not be more than 4 meter.
• M20 Grade of concrete should be used in concreting column.
• Fe 500 Steel is also recommended for column reinforcement.
• Column should be equally spaced in a grid so as to efficiently transfer the load.

Thumb Rule for Foundation

• Steel required in footing is 0.8% of total volume of concrete
• The clear cover of main reinforcement in footing is 50mm.
• A minimum 10mm bar shall be used for foundation footing.
• M20 grade of concrete or above should be used for foundation.
• Length, width and depth of foundation should not be less than 1 meter.
• Footing thickness should not be less then 40 cm.
• Pile foundation should be used if soil bearing capacity is less than 24 kN/m³.

Thumb Rule For Labour Productivity

Manpower productivity estimates are useful for calculating number of labour or man required to perform a task.

Labour output per day in construction activity can help to estimate the number of labour required to perform a particular work or task.

Manpower productivity estimates are shown below:

Sr. No.	Activity	Manpower	Output (8Hrs)
1.	Brickwork	Mason – 1 Male Mazdoor – 0.75 Female Mazdoor – 0.5	45 cuft
2.	Wall Plastering	Mason – 1 Male Mazdoor – 1 Female Mazdoor – 0.5	120 sqft
3.	Ceiling Plastering	Mason – 1 Male Mazdoor – 0.75 Female Mazdoor – 0.5	90 sqft
4.	Shuttering Work	Carpenter – 2.25 Foremen – 0.2 Helper – 2.25	11 m2
5.	Steel Work	Bar Bender – 1 Helper – 1	150 kg
6.	Tiling Work	Tile Mason – 1 Helper – 1	10 m2
7.	Block Work	Mason – 2 Male Mazdoor – 1.75 Female Mazdoor – 1.75	2 m3
8.	Earth Work	Male Coolie – 5 Female Coolie – 4	1000 cuft
9.	Painting Work	Painter Skilled – 1	600 sqft
10.	Carpenter	Carpenter skilled – 1 Helper – 1	4 m2
11.	Steel Binding	Fitter – 1 Helper – 1	250 Kg

From the above standard labour productivity in construction, we can calculate labour requirement and estimation.

Suppose for shuttering work, we need to know shuttering carpenter productivity per day. From the above thumb rule of labor,

For doing 11 m² of work, Shuttering carpenter productivity per day is,

• Carpenter – 2.25
• Foremen – 0.2
• Helper – 2.25

Thumb Rule For Steel Reinforcement

The calculation of steel is important as it is one of the costliest building materials. Important thumbrules for steel in building construction are shown below.

• Lapping is not allowed for the bars more then 36mm dia.
• Longitudinal reinforcement in structural members shall not be less then 0.8% and not more the 6% gross cross-sectional area.
• Atleast 4 bars should be used in square column and 6 bars in circular column section.

Important thumb rule for calculating steel based on building type and for structural members like slab, beam, column and footing is very useful.

Thumb rule for steel in building construction is shown below:

Sr. No.	Type of Building	Thumb rule for Steel (Kg/Sqft)
1.	Residential Building	4.5 – 4.75
2.	Commercial Building	5 – 5.5
3.	Heavy Structure or Tall Mass projects	6 – 8

The above thumb rule for steel in RCC estimation is not so accurate. For more approximate quantity of steel requirement refer B N Datta as shown below. Steel percentage in concrete as per IS code for different members is shown below:

Sr. No.	Member of Building	Percentage of Steel
1.	Slab	1% of Total Volume of Concrete
2.	Beam	2% of Total Volume of Concrete
3.	Column	2.5% of Total Volume of Concrete
4.	Footing	0.8% of Total Volume of Concrete

Example of steel requirement

Calculate steel requirement of slab of dimension 3m X 5m X 0.15m

Total volume of concrete = 3 x 5 x 0.15 = 2.25 m3

Steel required = 2.25 X 1% …(1% taken from table for slab)

=0.0225 m3

For weight of steel, multiply by the density of steel which is 7850kg/m3. As 1 cubic meter of steel weighs 7850 Kg.

Weight of steel required = 0.0225 X 7850 = 176.625 Kg

The weight of steel calculated from the above method is approximate, for accurate quantity use bar bending schedule.

Weight of Steel Bars Per meter length

For calculating weight of steel or reinforcement per unit length following thumbrules can be used.

Weight of steel = D²/162

For length L, Weight of r/f = (D²/162) X L

The weight of steel bars per unit length for different diameter of bars are shown below:

Sr. No.	Diameter of Bars	Weight of steel bar per meter
1.	6mm bar	0.222 kg
2.	8mm bar	0.395 kg
3.	10mm bar	0.616 kg
4.	12mm bar	0.888 kg
5.	16mm bar	1.578 kg
6.	20mm bar	2.466 kg
7.	25mm bar	3.853 kg
8.	32mm bar	6.313 kg
9.	40mm bar	9.865 kg

Thumb rule for steel quantity is shown below:

Thumb rule for steel in kg/m3 for 6mm dia bar is 0.222 Kg.

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Thumb Rule For Concrete

Concrete volume can be easily calculated if you know the plan area.

Thumb rule for calculating concrete volume = 0.038 m³ per square foot of plan area.

Thus if floor plan of a house is 30 X 20,

then total plan area= 600 sqft

volume of concrete = 600 X 0.038 m³ = 22.8 m³

Thus total volume of concrete to build 600 sqft house is 22.8 m³.

Concreting work can be done easily at site if the proportion of cement, sand and aggregate are known. Based on the mix design of concrete, ratio of cement, sand and aggregate changes, which can be seen in the table given below.

Concrete Mix	Ratio	Cement Qty (Bags)	Coarse Aggregate (m3)	Fine Aggregate (m3)
M5	1:5:10	2.82	0.98	0.49
M7.5	1:4:8	3.48	0.97	0.48
M10	1:3:6	4.50	0.90	0.45
M15	1:2:4	6.60	0.88	0.44
M20	1:1.5:3	8.40	0.84	0.42
M25	1:1:2	11.09	0.77	0.39

Thumb Rule For Concrete Mix Design

• In 1 cu.mt of freshly mixed concrete, if 4 liter of water is added then,

1. Slump value will increased by 25mm
2. Compressive strength of concrete will decrease by 1.5 N/mm² to 2 N/mm²
3. Shrinkage potential will be increased by 10%
4. 25% of cement bag will be wasted

• If temperature of freshly mixed concrete is increased by 1% then,

1. Slump will be equal to addition of 4 liter of water
2. Air content will be decreased by 1%
3. Compressive strength of concrete will decrease by 1 N/mm² to 1.5 N/mm²

• If air content of freshly mixed concrete is,

1. Increased by 1%, then compressive strength will be decreased by 5%
2. Decreased by 1%, then yield of concrete will be decreased by 0.03 m³ per 1 m³.
3. Decreased by 1%, then slump of concrete will be decreased by 12.5mm.
4. Decreased by 1%, then durability of concrete will be decreased by 10%.

Thumb Rule for Concrete Work

1. Volume of concrete required is 0.038 m³/sqft area.
2. Standard weight of 1 bag of cement is 50 kg.
3. 1 bag of cement is equal to 1.25 cuft or 0.0347 m³.
4. In high rise building 0.5 bags of cement is required per square feet of area.
5. Density of cement is 1440 kg/m³.
6. Specific gravity of cement is 3.15
7. Average cost of concrete is 50 to 80$ per cubic meter.
8. Initial setting time of cement is 30 minutes and final setting time of cement is 10 hrs.

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Thumb Rule for Shuttering Work

Shuttering is required for pouring concrete so that it take appropriate shape. Shuttering is important part of building construction.

Cost of shuttering is almost 15% to 18% of the total cost of building. Thus if shuttering quantity is not taken appropriately then it can lead to drain of money.

Thumb rule for shuttering is shown below

1. Shuttering is 6 time the concrete quantity or,
2. Shuttering is 2.4 times the plinth area

If we need to concrete 5 cubic meter then the shuttering required can be found with thumb rule by multiplying concrete quantity by 6.

Shuttering area = 5 X 6 = 30 m²

Shuttering Members

Different shuttering members are Ply, Battens, Nails.

Shuttering Ply

Shuttering Ply dimension are 2.44 m X 1.22 m X 0.012 m

Number of shuttering ply sheets needed for shuttering = 0.22 X Shuttering Area

Let’s assume we need to concrete 100m area. Then Shuttering needed for concreting is 0.22 time 100.

Ply required for shuttering = 0.22 X 100 = 22 numbers

Battens For Shuttering

General dimension of battens are 75mm X 40mm

Thumb rule for Batten Quantity = 19.82 X Number of Ply

For 22 number of ply, the quantity of battens is = 19.82 X 22 = 436 Battens

Nails and Binding Wire

• Thumb rule for nails required in shuttering is 75 grams per 1 m² of shuttering.
• Thumb rule for binding wire is 75 grams per 1 m² of shuttering area.

Shuttering Oil

Oil is applied on shuttering surface for easy removal of shuttering. Quantity of oil needed for shuttering is

• 0.065 times total shuttering area
• For 15 m² of shuttering, 1 liter of oil is needed

For 100m² of shuttering oil needed for shuttering = 0.065 X 100 = 6.5 liter

Sr. No.	Member	Thumb Rule
1.	Shuttering Area	6 times the concrete area or 2.4 times the plinth area
2.	Shuttering Ply	0.22 times Shuttering Area
3.	Battens	19.82 times Shuttering Ply
4.	Nails	75 grams per 1 m2 of shuttering area
5.	Binding Wire	75 grams per 1 m2 of shuttering area
6.	Shuttering Oil	0.065 times total shuttering area or For 15 m2 of shuttering, 1 liter of oil is needed

Thumb rule for removing Shuttering

Shuttering should be remoced only after the member has attained suitable strength. Below table mentions detail about removal of shuttering duration.

Sr. No.	Member of Structure	Days
1.	Sides of foundation, column, beams and walls	2 days
2.	Sides of span larger then 4.5 meter	14 days
3.	Sides of span shorter then 4.5 meter	7 days
4.	Sides of beams and arches upto 6 meter span	14 days
5.	Sides of beams and arches from 6 m to 9 m span	21 days
6.	Sides of beams and arches above 9 meter span	28 days

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Thumb Rule For Brickwork

Number of Bricks required in 1 cubic meter = 500 number

Suppose for 20m³ of brickwork is needed to be done

Then the quantity of brickwork required for 20m³ of brickwork = 20 X 500 = 10000 bricks.

Thus 10000 number of bricks is required for brickwork of 20m³.

Quantity of cement required in 1 m³ of brickwork for different size of brickwork varies. Below is a thumbrule for brickwork cement required.

Sr. No.	Brickwork size	Cement required (m3)	Cement Quantity (Bags)
1.	230mm Brickwork	0.876 m3	25.4
2.	115 mm Brickwork	0.218 m3	6.32

Thumb Rule for Brickwork for different mix ratio thickness of brickwork along with cement sand required are given below.

Sr. No.	Brickwork	Mix Ratio	Mortar Thick (mm)	Cement Qty (Bags/m3)	Sand (m3)
1.	100 mm thick	1:4	10	0.15	0.035
2.	200 mm thick	1:6	10	1.4	0.30
3.	200 mm thick	1:5	10	1.7	0.25
4.	200 Blockwork	1:5	10	0.15	0.02

Thumb rules of bricks

• Standard size of bricks is 19cm X 9cm X 4cm.
• Weight of first-class clay bricks should be 3.85 kg.
• Crushing strength of bricks is 10.5 MN/m².
• Water absorption in bricks is 12% to 15%.
• Compressive strength of bricks is 36 KN/cm².
• Number of bricks in 1m³ of brick masonry is 550 bricks.

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Thumb Rule For Plastering

Based on experience and practice following thumb rule for plastering is used in construction and building work.

Cement required changes according to type of plastering. Cement required for internal plastering is comparatively lower then cement required for external plastering.

Below is a table containing cement requirement for different type of plastering work.

Sr. No.	Plastering Type	Cement Qty (Bags/m2)	Cement Qty (Kg/m2)
1.	Internal Plastering	0.09	4.5
2.	External Plastering	0.175	8.75
3.	Rough Plastering	0.09	4.5
4.	Duct Plastering	0.09	4.5
5.	Lathen Plastering	0.55	27.5
6.	Stucco Plastering	0.175	8.75

Cement sand requirement for wall and ceiling plastering are shown below:

Sr. No.	Plastering Type	Ratio	Plaster Thickness (mm)	Cement (Bags/m2)	Sand (m3/m2)
1.	Internal wall Plaster	1:3	15	0.16	0.017
2.	External Wall Plaster	1:4	20	0.17	0.024
3.	Ceiling Plaster	1:2	12	0.17	0.012
4.	Rough Plaster	1:5	16	0.11	0.020

Thumb Rule For Cement Masonry Work

Cement requirement in masonry work varies according to cement masonry type and mix. Quantity of cement required for different cement masonary work and mix is shown below.

Sr. No.	Masonry Type and Mix	Cement Qty (Bags/m2)	Cement Qty (Kg/m2)
1.	200mm Masonry Work (1:6)	0.124	6.20
2.	150mm Masonry Work (1:6)	0.093	4.65
3.	200mm Masonry Work (1:4)	0.206	10.30
4.	150mm Masonry Work (1:4)	0.144	7.20
5.	100mm Masonry Work (1:4)	0.103	5.15

Thumb Rule for Flooring

Quantity of cement required for laying of flooring can be calculated based on the thumb rule given below.

Sr. No.	Type of Flooring	Thumb Rule for cement
1.	Marble Flooring	0.3 Bags/m2
2.	Marble Skirting	0.025 Bags/m
3.	Marble Glading	0.27 Bags/m2
4.	Terrace Flooring	0.3 Bags/m2
5.	Granolithic Flooring	0.25 Bags/m2
6.	Mangalore Tile	0.35 Bags/m2
7.	Ceramic Flooring	0.3 Bags/m2
8.	Vitrified Tile Flooring	0.28 Bags/m2
9.	Vitrified and ceramic tile dado	0.25 Bags/m2
10.	Anti skid Flooring	0.28 Bags/m2

Thumb Rule for Water Proofing

Sr. No.	Water Proofing work	Thumb rule
1.	Water proofing for sunk slab	0.25 Bags/m2
2.	Water proofing for walls	0.25 Bags/m2
3.	Water proofing for toilets	0.63 Bags/m2

Thumb Rule for Cement

Bulk Density of Cement

Density of cement according to type are shown below:

Sr. No.	Cement Types	Density (kg/m3)	Density (KN/m3)
1.	Lime mortar	1600-1840	16-18
2.	Ordinary Cement	1440	14.4
3.	Plain Cement Concrete	2400	24
4.	Pitch	1010	10.1
5.	RCC	2500	25

Below is a list of cement types and initial and final setting time of respective cement.

Sr. No.	Type of Cement	Initial Setting Time	Final Setting Time
1.	Ordinary Portland Cement (33 Grade)	30 minute	600 minute
2.	Ordinary Portland Cement (43 Grade)	30 minute	600 minute
3.	Ordinary Portland Cement (53 Grade)	30 minute	600 minute
4.	Sulphate Resistant Cement	30 minute	600 minute
5.	Portland Pozzolona Cement	30 minute	600 minute
6.	Rapid Hardening Cement	30 minute	600 minute
7.	Slag Cement	30 minute	600 minute
8.	High Alumina Cement	30 minute	600 minute
9.	Super Sulphated Cement	30 minute	600 minute
10.	Low Heat Cement	60 minute	600 minute
11.	Masonry Cement	90 minute	600 minute
12.	IRS T-40	60 minute	600 minute

Thumb rule for Achieving Economy

In order to save money in building construction, one has to follow certain guidelines and thumb rule. Following these thumb rules for building construction will result in saving money and economic building.

1. Use formwork as many time as possible to achieve economy.
2. Minimum floor to floor height will result in saving of money.
3. Column layout should be placed in a uniform grid.
4. Standard column size should be used.
5. Same depth of beam should be used, if possible.
6. Local available material should be used to minimise cost.
7. High strength concrete should be used.
8. To remove formwork earlier high early strength concrete should be used.
9. To minimise honey combing and air pockets in concrete self consolidating concrete should be used.
10. Avoid congestion of steel especially at beam column joints.
11. Use large size bars in column and smaller size bars in slab.

Frequently Asked Questions

Some of the most frequently asked question in civil engineering are shown below.