# PARAM VISIONS

All about civil construction knowledge- PARAM VISIONS

### 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 inch.

=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 the wall.

Dry volume of the cement mortar = 1.33 × wet volume of the mortar.

= 1.33 × 6.697

= 8.907 cu.ft.

So, volume of the sand

= (6  ÷ ( 6 + 1)) × 8.907

= 0.8571 × 8.907

= 7.634 cu.ft.

Volume of the cement

= total dry mortar vol. - 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.