Baxi Baby Bevelled Brick

Baxi Baby Bevelled Brick Size of both bricks is 150mm Long x 75mm Deep x 40mm Thick ? if you add 10mm to allow for a joint I would use 160mm x 50mm (6.4? x 2?) for each brick which equates to (in inches) 12.8 sq ? . 1sq m = 39? x 39? = 1521 sq ? So Divide 1521 / 12.8 = 118.82 or 119 Bricks per sq metre.