Thumb Rules for Civil Engineering

Thumb Rules For Civil Site Engineers

Thumb Rules For Civil Engineering is essential for any civil engineer, Site engineer, or civil supervisor. They play a crucial role while taking quick decisions on-site. There is some civil engineering basic knowledge that every civil engineer must know.

The thumb rule for construction helps you in finding out the solution using a simple mathematical formula and make smart decisions whenever needed.

But, while using these thumb rules, you must remember that the thumb rule never gives exact or accurate results, you just have used them for approximate results.

There is a number of Thumb Rule For Civil Engineers that we used in construction work. So, the following are some most frequently used Thumb rules on the Construction site.

The Thumb rule method is an approximate & comparing method. In thumb rules and the units are not the same when we compare to get the results. So, ignore units while performing the thumb rule.

Read More: Tips for Civil Site Engineers

Thumb Rules for Civil Engineering In Construction

The thumb rules in civil engineering are as follows,

1. Thumb Rule for Concrete Volume

The volume of concrete required = 0.038 m3/square feet area

Example:- If Plan Area = 40 x 20 = 800 Sq. m.

So, for the plan area of 800 Sq. m. the area the total volume of concrete required.

= 800 x 0.038m3 = 30.4m3

2. Thumb Rule for Steel Quantity for Slab, Beams, Footings & Columns

Following are some important thumb rules for steel calculation for slab, beam, column, and footings.

Steel required in residential buildings = 4.5 Kgs – 4.75 Kgs / sq. Ft.

Steel required For Commercial buildings = 5.0 Kgs-5.50 Kgs/Sq. Ft.

You can also use BN Datta recommendations for the more accurate result,

The following recommendations Thumb Rules For Civil Engineering are given in B N Datta for the Steel quantity used in different members of the building.

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3. Percentage of Steel in Structural Members

Following are thumb rules for reinforcement in concrete members,

1) Slab – 1% of the total volume of concrete (Slab steel calculation thumb rule)
2) Beam – 2% of the total volume of concrete
3) Column – 2.5% of total volume of concrete
4) Footings – 0.8% of the total volume of concrete

Example:

How to calculate the steel quantity of slab having the Length, width, and depth of the slab is 5m x 4m x 0.15m

Step 1: Calculate the Volume of Concrete:

The Total Volume of Concrete for the given Slab = 5 x 4 x 0.15

= 3m³

Step 2: Calculate The Steel Quantity Using the Formula:

As per the guidelines given in the BN Dutta reference book the steel quantity of the slab is 1% of the total volume of concrete utilized.

A thumb rule to estimate the Steel quantity of the above slab = Volume of Concrete x Density of Steel x % of Steel of the Member

Steel weight required for above slab = 3 x 7850 x 0.01 = 235Kgs

For accurate estimation, you can refer to Bar Bending Schedule

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4. Thumb Rules For Shuttering Work

Shuttering costs are taken as 15-18% of the total construction of the building. Shuttering work is done to bring the concrete into Shape. The Thumb rule to estimate the shuttering required is 6 times the quantity of concrete or 2.4 times the Plinth area.

For example, if the concrete quantity is 0.5m³, then

Area of Shuttering is 0.5 x 6 = 3m²

Components of Shuttering

Shuttering Ply Quantity estimation

The Shuttering plate Ply, Battens, and Nails are components of Shuttering.

Suppose, The Shuttering Ply has a length, width & depth of 2.44 x 1.22 x 0.012

The No. of Shuttering Ply Sheets = 0.22 times of Shuttering

Suppose, the Shuttering Area = 3m

Then Ply required for shuttering = 0.22 x 3 = 0.66m²

5. Battens Quantity Calculation

Shuttering Batten usually has a length & width of 75mm x 40mm.

Batten Quantity = 19.82 x No. of Ply Sheets

If work requires 25 Ply sheets, the total quantity of Battens is 19.82 x 25 = 495 Battens

Nails & Binding Wire Quantity in Shuttering:

Approximately, 75 grams of Nails were used in the shuttering of the 1m² area.

75gms of Binding wire is used for every 1m² of Shuttering.

The thumb rule for Shuttering oil estimation :

Shuttering oil is applied on the shuttering plate surface used to de-frame or de-assemble from the concrete easily.

Total required Shuttering oil  = 0.065 x Total Area of Shuttering

(or)

For every 15m² of shuttering 1 liter of shuttering oil is consumed.

Example :

If, total area of shuttering is 15 m2, then Shuttering oil Consumption = 0.065 x 15 = 0.975.

Read More: 17 Tips For How To Reduce Construction Cost

6. Thumb Rule for Cement, Sand, Coarse Aggregate Quantity Calculations

Note: 1 bag of cement = 50Kgs

Thumb rule for Cement required in Brickwork, Cement Masonry & Plastering work in construction

7. Thumb Rules For Civil Engineers for Brickwork

The following are Thumb Rules for civil engineering for brickwork and cement quantity calculations.

Brickwork for 1m3	Cement Qty in m3	Cement Qty in Bags
230 mm Brickwork	0.876m3	25.4 Bags
115 mm Brickwork	0.218m3	6.32 Bags

8. Thumb Rules For Cement Masonry Quantity

Cement Masonry Type & Mix	Cement Qty in Bags	Cement Qty in Kgs
200mm in Cement Masonry work of Ratio 1:6	0.124Bags/m2	6.2Kgs/m2
150mm in Cement Masonry work of Ratio 1:6	0.093Bags/m2	4.65Kgs/m2
200mm in Cement Masonry work of Ratio 1:4	0.206Bags/m2	10.3Kgs/m2
150mm in Cement Masonry work of Ratio 1:4	0.144Bags/m2	7.2Kgs/m2
100mm in Cement Masonry work of Ratio 1:4	0.103Bags/m2	5.15Kgs/m2

8. Thumb Rules Plastering Quantity

Type of Plastering	Cement Qty in Bags	Cement Qty in Kgs
Rough Plastering	0.09 Bags/m2	4. 5Kgs/m2
Internal Wall Plastering	0.09 Bags/m2	4.5 Kgs/m2
Duct Plastering	0.09 Bags/m2	4.5 Kgs/m2
External Wall plastering	0.175 Bags/m2	8.75 Kgs/m2
Stucco Plastering	0.175 Bags/m2	8.75 Kgs/m2
Lathen Plastering	0.55 Bags/m2	27.5 Kgs/m2

9. Thumb Rules In Building Construction Cost

The thumb rule for house construction cost is a rough estimation of the total cost of construction based on the built-up area of the house. Typically, thumb rules are quick and easy to use but are not precise and may not take into account specific factors that affect the actual cost of construction.

As an approximate guide, a common thumb rule for house construction cost is between Rs. 1500 to Rs. 2500 per square foot, depending on factors such as the quality of materials used, location, design, and labour costs. This would mean that a 1000 square feet house may cost between Rs. 15 lakhs to Rs. 25 lakhs.

Below is a general thumb rule that can be used to estimate the building materials and work required for a given unit area of construction.

Sr. No.	Material/ Work	Thumb Rule
1.	Cement (bags)	0.43 bags / sq ft
2.	Sand (cu.ft)	2.5 kg / sq ft
3.	Aggregate (cu.ft)	1.20 cu ft / sq ft
4.	Steel (kg)	1.34 cu ft / sq ft
5.	Bricks (Nos.)	7.3 no / sq ft
6.	Tiles (Nos.)	0.7 nos / sq ft
7.	Colour (Liters)	0.12 lit / sq ft
8.	Finishing Works	₹ 470/sq ft
9.	Electrical Cost	₹ 250 /sq ft
10.	Plumbing Cost	₹ 150 /sq ft
11.	Fire Fighting Cost	₹ 45 /sq ft
12.	Exterior Cost	₹ 94.5 / sq ft

Thumb Rule according to materials percentages,

Description	Thumb rule (% of Total Cost)
Cement	14.4%
Sand	12.3%
Aggregate	7.4%
Steel	20.6%
Painting material	5.1%
Tiles	8%
Bricks	5.4%
Window	3%
Doors	4.4%
Plumbing	7.5%
Electrical	6.8%
Sanitary	4.1%

Thumb rules for construction cost

The cost of construction can vary depending on the quality of materials and workmanship used. Below is an overview of the average construction costs based on the quality of construction. This information can serve as a useful reference point for estimating the costs of a building project.

Sr. No.	Construction based on Quality	Thumb Rule
1.	Basic Quality Construction	1000 Rs./Sqft
2.	Medium Quality Construction	1300 Rs./Sqft
3.	High Quality Construction	1700 Rs./Sqft

1000 Sqft House average cost of construction Thumb Rule

Sr. No.	Description of Work	1000 sq ft House Average Cost
1.	Architectural Cost	Rs. 12,500 Onwards
2.	Brick wall Construction without RCC	Rs. 700 per sqft
3.	Brick wall Construction With RCC	Rs. 850 per sqft
4.	Civil Construction Work	Rs. 1400 per sqft
5.	Electric and Plumbing Work	Rs. 2400 per sqft
6.	Raw Material Cost In Construction	Rs. 8 Lakh Onwards

A common approach to estimating building costs is to use a thumb rule based on the percentage of the total project cost. This method provides a rough estimate of the building cost and is often used as a starting point for budgeting purposes.

Sr. No.	Work	Cost
1.	Excavation and Filling Earthwork	0.6%
2.	Foundation Work	4.9%
3.	DPC	1.2%
4.	Brick work	32%
5.	Roofing	22%
6.	Flooring	5%
7.	Doors and window	17%
8.	Plastering	9%
9.	White Washing	3%
10.	Miscellaneous	5.5%

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