For a 1⅟2 brick thickiness wall (i.e. 30cm nominal thickness). Therefore nominal volume of wall of 20m length , 1m height & 0.3m thickness
= 20 x 5 x 0.3 = 30 cu.m.
Normally mortar joint will be less than 1cm, but assuming mortar joint as 1cm thickness, then actual thickness of wall will be = 29cm. therefore , actual thickness = 20 x 5 x 0.29 = 29 cu.m.
Nominal Size of standard brick = 20cm x 10cm x 10cm.
Number of std bricks = 29/(0.20 x 0.10 x 0.10) = 14500
Then,
Number of bricks per cu.m(nominal) = 14500/30 =483.3333
=483 bricks.
Considering 5% breakages, wasteges,etc (assume)
So,Number of bricks required for 1 cu.m = 500 bricks
RESULT:
Therefore, number of bricks required for 1 cu.m = 500 bricks .