Page 160 - Masonry and Concrete

Masonry Construction Techniques
159
MASONRY CONSTRUCTION TECHNIQUES

last brick or block in the middle of a course, all edges of the opening
and all vertical edges of the unit should be buttered with mortar and
the unit carefully lowered into place. If any of the mortar falls out,
leaving a void in the joint, the closure unit should be removed and the
operation repeated.
In cavity wall and veneer wall construction, it is extremely impor-
tant that the cavity between the outer wythe and the backing wall be
kept clean to assure proper moisture drainage. If mortar clogs the cav-
ity, it can form bridges for moisture passage to the backing wall, or it
may block weep holes. Some masons use a removable wooden strip to
temporarily block the cavity as the wall is laid up and prevent mortar
droppings. However, beveling the mortar bed as shown in Figure 5-20
allows little mortar to extrude toward the cavity.
To add visual interest to masonry walls, units may be laid in differ-
ent positions as shown in Figure 5-5, and arranged in a variety of pat-
terns as shown in Figure 5-7. The patterns were originally conceived
in connection with masonry wall bonding techniques that are not
widely used today. In older historic masonry, rowlock and header
courses were used to structurally connect multiple wythes of a thick
1
1
masonry wall together. Most contemporary buildings use the 3 or 2

FIGURE 5-22
Hollow masonry units are typically laid with face shell bedding. (Photo courtesy PCA).

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