PART E - CONTROL JOINTS
Control joints are continuous vertical joints that are built into concrete-blocks walls to control cracking
from unusual stress. They are usually spaced at 20- to 25-foot intervals in long walls and extend to the
top course. A wall shorter than 20 feet does not normally require a control joint.
2-12. Using Full- and Half-length Blocks. Use full- and half-length blocks to form a continuous
vertical joint which will permit slight wall movement without cracking. You should lay control joints
up in mortar just like any other joint (Figure 2-11).
Figure 2-11. A control joint using full- and half-length blocks