# 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.

Structural Member | Percentage of Steel |
---|---|

Slab | 1% of total volume of concrete |

Beam | 2% of of total volume of concrete |

Column | 2.5% of total volume of concrete |

Footings | 0.8% of 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 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 m^{3}

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 :

Concrete Mix | Cement Quantity | Coarse Aggregate Quantity | Fine Aggregate Quantity |
---|---|---|---|

M5 (1:5:10) | 2.82 Bags | 0.98m^{3} | 0.49m^{3} |

M7.5(1:4:8) | 3.48 Bags | 0.97m^{3} | 0.48m^{3} |

M10(1:3:6) | 4.50 Bags | 0.90m^{3} | 0.45m^{3} |

M15(1:2:4) | 6.60 Bags | 0.88m^{3} | 0.44m^{3} |

M20(1:1.5:3) | 8.40 Bags | 0.84m^{3} | 0.42m^{3} |

Note: 1 bag of cement = 50Kgs

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

The Concrete Volume of 0.038m^{3 }of 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 0.038m^{3} =** 15.2 m ^{3}**

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

## Brickwork Thumb rule:

Brickwork for 1m^{3} | Cement Qty in m ^{3} | Cement Qty in Bags |
---|---|---|

230 mm Brickwork | 0.876bags/m^{3} | 43.80kgs |

115 mm Brickwork | 0.218bags/m^{3} | 10.90kgs |

## Cement Masonry Quantity Thumb Rule:

Cement Masonry Type & Mix | Cement Qty in Bags | Cement Qty in Kgs |
---|---|---|

200mm in Cement Masonry work of ratio 1:6 | 0.124Bags/m^{2} | 6.2Kgs/m^{2} |

150mm in Cement Masonry work of ratio 1:6 | 0.093Bags/m^{2} | 4.65Kgs/m^{2} |

200mm in Cement Masonry work of ratio 1:4 | 0.206Bags/m^{2} | 10.3Kgs/m^{2} |

150mm in Cement Masonry work of ratio 1:4 | 0.144Bags/m^{2} | 7.2Kgs/m^{2} |

100mm in Cement Masonry work of ratio 1:4 | 0.103Bags/m^{2} | 5.15Kgs/m^{2} |

## Plastering Quantity Thumb Rule:

Type of Plastering | Cement Qty in Bags | Cement Qty in Kgs |
---|---|---|

Rough Plastering | 0.09Bags/m^{2} | 4.5Kgs/m^{2} |

Internal Wall Plastering | 0.09Bags/m^{2} | 4.5Kgs/m^{2} |

Duct Plastering | 0.09Bags/m^{2} | 4.5Kgs/m^{2} |

External Wall plastering | 0.175Bags/m^{2} | 8.75Kgs/m^{2} |

Stucco Plastering | 0.175Bags/m^{2} | 8.75Kgs/m^{2} |

Lathen Plastering | 0.55Bags/m^{2} | 27.5Kgs/m^{2} |

## 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 m^{3} then the shuttering area required is 1.5 x 6 = 9m^{2}

**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 m^{2}

**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 1m^{2} of Shuttering

75gms of Binding wire is consumed for every 1m^{2} 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 15m^{2} of shuttering 1 litre of shuttering oil is consumed.

**Example :**

10m^{2} is total area of shuttering, then Shuttering oil required = 0.065 x 10 = 0.65 lts