Calculating the quantity of materials in a 100 cubic ft. block wall./Block, cement & sand calculations for a wall masonry.

 Let us consider a concrete block wall of size 10ft × 20 ft.× 0.5 ft. as shown in the figure.

Solid block wall.

Here, length L = 20 ft., height H = 10ft., &  thickness T = 0.5 ft ( 6 inches ).

Now, we will build this wall with a concrete block of size 16 inches × 8 inches × 6 inches as shown in the figure below.

Solid concrete block.

Here, length l = 16 inches, height h = 8 inches, & thickness t = 6 inches.

To calculate the number of concrete blocks required to build this wall, first, we will find out the volume of the wall and the volume of a single block with or without mortar.

The volume of the block wall 

                  = L × H × T 

                  = 20ft × 10ft × 0.5 ft.

                  = 100cft.

Now,

 the volume of the concrete block

                 = l × h × t

                 = 16 inches × 8 inches × 6 inches 

                    ( By converting them into ft.)

                 = 1.333ft × 0.666 ft × 0.5 ft.

 

                 =0.4443 cft.

From fig. given below, you can observe that the addition of the mortar thickness comes on the 2 sides of every block.

 

So, the volume of the block with mortar

                     = 16.375inches ×8.375 inches × 6 inches

                     =822.84375 cubic inches.

                     =0.476182cu.ft.

 

Now, the number of blocks required

                  = [volume of the wall ÷ volume of the block with mortar]

                  = [100 ÷ 0.476182] 

                  =210 nos.

The volume of mortar required 

        = [volume of the block wall - the volume of the total no. of blocks ]

        = [100 cu.ft. - (210 nos. × 0.4443 cu.ft.)]

        =   [100 - 93.303]

           =6.697 cu.ft.

Let us prepare this 6.697 cu ft. of mortar in a 1: 6 ratio to build this 100 cu ft. of wall.

The dry volume of the cement mortar = 1.33 × wet volume of the mortar.

          = 1.33 × 6.697

           = 8.907 cu.ft.

So, the volume of the sand

          = (6  ÷ ( 6 + 1)) × 8.907

           = 0.8571 × 8.907

            = 7.634 cu.ft. 

The volume of the cement 

   = total dry mortar vol. - the volume of sand

    = 8.907cu.ft - 7.634cu ft.

    =1.273 cu.ft.

As you know, one bag of cement = 1.226 cu ft.

  Number of cement bags 

    = 1.273 ÷ 1.226 

    =   1.038bags.

                    

     To go through all types of quantity estimate articles, click here.

Thank you for going through these calculation steps❤. Have a good day 😄.   

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