Page 329 - Masonry and Concrete

Masonry Garden Walls

328 CHAPTER NINE

FIGURE 9-17
Single-wythe CMU wall.

two wythes of 4-in. block (Figure 9-18). Concrete block walls need wire
joint reinforcement to help minimize shrinkage cracking. The two
wythes of a double-wythe wall can also be tied together by the joint rein-
forcement. For best performance, joint reinforcement should be installed
in every second or third bed joint throughout the height of the wall,
beginning with the second course. Like metal ties, joint reinforcement
must be completely embedded in the mortar to develop its full strength.
If it is laid on dry units and mortar is simply spread on top, the joint rein-
forcement will not be properly bonded and cannot provide adequate
restraint. Where joint reinforcement must be overlapped to splice two
sections, lay the wires side by side in the joint and overlap them about 16
in. The width of the joint reinforcement should be about 1 in. less than

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