# Thumb Rules used in Construction For Civil Engineers | Read Here

#### Thumb rule to calculate the Steel quantity required for Slab, Beams, Footings & Columns:

For Residential buildings :- 4.5Kgs-4.75Kgs /SFT

For Commercial buildings :- 5.0Kgs-5.50Kgs/SFT

As per B N Datta, the Steel quantity used in different members of the building can be calculated easily using the following recommendations.

#### Example:

How to calculate the steel quantity of slab having the Length, width, and depth of the slab is 5m x 2m x 0.15m

Step 1: Calculate the Volume of Concrete

Total Volume of Concrete for above given Slab is 5 x 2x 0.15 = 1.5 m3

Step 2: Calculate the steel quantity using formula

As per the above table, the steel quantity of slab is 1% of the total volume of concrete utilized.

Thumb rule to calculate Steel quantity of above slab = Volume of Concrete  x Density of Steel x % of Steel of Member

Steel quantity required for above slab = 1.5 x 7850 x 0.01 = 117.7 Kgs

#### Thumb rule for Cement, Sand, Coarse Aggregate Quantity in Different grades of Concrete :

Note: 1 bag of cement = 50Kgs

## Thumb rule to calculate the Concrete Volume with respect to area:

The Concrete Volume of 0.038mof concrete is used for each Square Feet of Plan area

Example:-

From below fig: Plan Area = 20 x 20 = 400SFT

The plan area is 400SFT then the total volume of concrete required = 400 x 0.038m3 = 15.2 m3

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

## Thumb rule to calculate the Shuttering area:

Shuttering costs 15-18% of the total construction of the building. Shuttering is framed to bring the concrete in Shape. Thumb rule to calculate the shuttering required is 6 times the quantity of concrete or 2.4 times of Plinth area.

Suppose, the concrete quantity is 1.5 m3 then the shuttering area required is  1.5 x 6 = 9m2

Components of Shuttering:-

Shuttering Ply, Battens, Nails are components of Shuttering.

### Shuttering Ply Quantity calculation:

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 area of shuttering required = 2m2

Then the Shuttering Ply required = 0.22 x 2 = 0.44 m2

### Battens Quantity Calculation:

Shuttering batten usually have a length & width of 75mm x 40mm.

Batten Quantity = 19.82 x No. of Ply Sheets

if the construction requires 25 Ply sheets, the total quantity of Battens are 19.82 x 25 = 495 Battens

### Nails & Binding Wire Quantity in Shuttering:

75gms of Nails are used for 1m2 of Shuttering

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

### Thumb rule for Shuttering oil Quantity:

Shuttering oil is used to de-frame or de-assemble from the concrete easily.

Total required Shuttering oil is = 0.065 x Total Area of Shuttering

(or)

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

Example :

10m2 is total area of shuttering,  then Shuttering oil required = 0.065 x 10 = 0.65 lts