How To Calculate Number Of Concrete Blocks In A Wall


Number Of Concrete Blocks In A Wall

There are several methods for calculating the number of blocks in a wall. In this article, I will explain two simple methods to find out the total no. of blocks for a wall.

The two methods are as follows:

  1. Surface area method.
  2. Volume method.

Let’s calculate the number of concrete blocks one by one.

1. Calculation By Surface Area Method

Required Data:

  • Surface area of the wall.
  • Surface area of a standard concrete block.
  • Surface area of openings in the wall.
Step 1:
Determine The Length & Height Of The Wall:

Let the Length of the wall = 10 feet.

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The height of the wall = 10 feet.

Step 2:
Calculate The Surface Area Of The Wall:

We know, Surface Area = Length x Height

∴ Surface area of the wall = 10 x 10 = 100 sq. feet.

Step 3:

Calculate The Surface Area Of Openings:

If the wall has any openings such as doors, windows, etc, calculate the surface area of openings.

Let the wall has a window of 3′ x 3′

∴ Surface area of the window = 3 x 3 =9 sq. ft

Step 4:

Subtract The Surface Area Of Openings From Surface Area Of Walls:

∴ Final Surface Area of wall = 100 – 9 = 91 sq.ft.

Step 5:

Calculate The Surface Area Of A Concrete Block With Mortar Allowance:

Let the block is 16″ x 8″ x 8″ and mortar allowance is 1″

∴ Surface Area of one block with mortar = (16+1) x (8+1)= 153 inch²

= 153/12×12 = 1.0625 sq.ft

Step 6:

Divide The Total Surface Area Of The Wall By Surface Area Of One Block:

∴ Number of blocks = Surface Area of wall/Surface Area of a block = 91/1.0625 = 86

Consider 5% wastage of concrete blocks.

So the total numbers of blocks required = 86 + (86 x 5/100) = 86 + 4 = 90.


2. Calculation By Volume Method

Required Data:

  • Volume of the wall.
  • Volume of a standard concrete block.
  • Volume of openings in the wall.
Step 1:

Determine The Width, Height, And Thickness Of The Wall:

Let, the width of the wall = 10 feet.

The height of the wall = 10 feet.

The thickness of the wall = 8″ = 0.67 feet. [ Thickness of the wall will be same as the thickness of one concrete block]

Step 2:

Calculate The Volume Of The Wall:

We know, Volume = Width x Height x Thickness

∴ Volume of the wall = 10 x 10 x 0.67 = 67 cubic feet.

Step 3:

Calculate The Volume Of Openings:

If the wall has any openings such as door, windows, etc, calculate the volume of openings

Let the wall has a window of 3′ x 3′ x 0.67′ [ Thickness of the window will be the same as the thickness of the wall]

∴ Volume of the window = 3 x 3 x 0.67 =6 cu. ft

Step 4:

Subtract The Volume Of Openings From Volume Of Walls:

∴ Final volume of wall = 67 – 6 = 61 cu.ft.

Step 5:

Calculate The Volume Of A Concrete Block With Mortar Allowance:

Let the block is 16″ x 8″ x 8″ and mortar allowance is 1″

∴ The volume of one block with mortar = (16+1) x (8+1) x 8 = 1224 inch3 [The mortal will be given on the upper side and one side of every concrete block]

= 1224/12x12x12 = 0.70 cu.ft

Step 6:

Divide The Total Volume Of The Wall By Volume Of One Block:

∴ Number of blocks = Volume of wall/Volume of a block = 61/0.70 = 86

Consider 5% wastage of concrete blocks.

So the total numbers of blocks required = 86 + (86 x 5/100) = 86 + 4 = 90.

Note:

If the wall does not have any opening skip step 4, and just divide the surface area of the wall by the surface area of one block.

Also Read
How To Calculate Concrete For Staircase

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26 thoughts on “How To Calculate Number Of Concrete Blocks In A Wall”

    • Hi sir

      Lengt of wall is 15m wide is 5.5m hight 3m
      Lengt 15m high 3m

      1 How many redbricks and how many aac concrete blocks
      Do I need.
      2 how many bags of cement 25 kg do I need.
      3 how many ton of buildingsand do I need.

      My floor is 5.5 by 15 wide how thick it haze be for concrete floor. How many mash sheet do I need. To not to have kracks in floor. What tick of steel I need to use

      Hope to get answer back
      Thank

      Reply
  1. Using the Surface Area Method, I don’t understand how you got the 12 in step 5

    153/12×12 = 1.0625 sq.ft.

    Thanks.

    Reply
    • 153 Ich2 was converted to square foot
      in each 1 inch there’s 0.0833 feet
      d(ft)/12 is the formula for converting an inch to feet
      but here we have Inch2
      therefore, 153/12×12 = 1.0625 Sq.ft.

      Reply

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