In building a wall it is usual to lay bricks in regular, horizontal courses
so that each brick bears on two bricks below. The bricks are said to be bonded as they bind together by being laid across each other along the length of the wall, as illustrated in Fig. 50.
The advantage of bonding is that the wall acts as a whole so that the load of a beam carried by the topmost brick in Fig. 50 is spread to the two bricks below it, then to the three below that and so on down to the base or foundation course of bricks.
The failure of one poor quality brick such as ‘A in a wall and a slight settlement under part of the foundation such as ‘B’ and ‘C in Fig. 50 will not affect the strength and stability of the whole wall as the load carried by the weak brick and the two foundation bricks is transferred to the adjacent bricks.
The effect of bonding is to stiffen a wall along its length and also to some small extent against lateral pressure, such as wind.