Calculating the number of concrete blocks in a wall. /Estimating the no. of hollow blocks in a masonry wall.

 Let us consider a concrete block wall of size 10ft × 24 ft.× 0.5 ft. as shown in the figure.

Here, length L = 24 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.

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 mortar.

The volume of the block wall 

                  = [L × H × T ]

                  = [24ft × 10ft × 0.5 ft.]

                  = 120cft.

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.

To find out the total number of concrete blocks, we have to include the volume of the mortar used in the masonry work. 

The thickness of the mortar we use in this masonry work is 1 inch, having the same length & height as that of the concrete block. 

So, the volume of the concrete block inclusive of the mortar volume is calculated as,

= 17 inches × 9 inches × 6 inches. 

As you can see in fig. below, the mortar thickness of 1 inch is added to the length & height of the individual block ( green color  )

              = [1.4166ft × 0.75 ft × 0.5 ft.]

                 ( By converting them into ft.)

             = 0.531 cft.

       Now, the number of concrete blocks required

            = [volume of the block wall ÷ volume of the concrete block inclusive of mortar.]

            =  [120cft ÷ 0.531 cft. ]

      

            = 225.98 say 226 nos.

Adding 3% extra as wastage,

          = [226 +((226 × 3 ) ÷ 100)]

          =  [226 nos. + 8 nos.]

          = 234 nos.

Alternate method :

As the thickness of the wall is equal to the concrete block thickness, we can calculate the number of blocks by considering the surface area.

The surface area of the block wall

         = [L × H ]

         = [24 ft. × 10ft.] 

 

        = 240 sq.ft.

The surface area of the concrete block inclusive of the mortar

         = [17 inches × 9 inches] 

         = [1.4166 ft × 0.75 ft.]

        = 1.062 sq.ft.

Number of blocks required

         = [surface area of wall  ÷ surface area of block plus mortar]

         = [240  ÷ 1.062]

      

         = 226 nos.

Adding 3%  as wastage 

         = [226nos + 8nos ]

         = 234 nos.

 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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