suited to walls or partitions in hospitals, dairies,
laboratories, and other structures requiring sanitary
conditions and ease of cleaning.
Fire brick is made from a special type of clay.
This clay is very pure and uniform and is able to
withstand the high temperatures of fireplaces, boilers,
and similar constructions. Fire bricks are generally
huger than other structural bricks and are often hand
Cored bricks have ten holestwo rows of five
holes each-extending through their beds to reduce
weight. Walls built from cored brick are not much
different in strength than walls built from solid brick.
Also, both have about the same resistance to moisture
penetration. Whether cored or solid, use the more
available brick that meets building requirements.
European brick has strength and durability about
equal to U.S. clay brick. This is particularly true of
the English and Dutch types.
Sand-lime brick is made from a lean mixture of
slaked lime and fine sand. Sand-lime bricks are
molded under mechanical pressure and are hardened
under steam pressure.
These bricks are used
extensively in Germany.
STRENGTH OF BRICK MASONRY
The main factors governing the strength of a brick
structure include brick strength, mortar strength and
elasticity, bricklayer workmanship, brick uniformity,
and the method used to lay brick. In this section,
well cover strength and elasticity. Workmanship is
covered separately in the next section.
The strength of a single brick masonry unit varies
widely, depending on its ingredients and manu-
Brick can have an ultimate
compressive strength as low as 1,600 psi. On the
other hand, some well-burned brick has compressive
strength exceeding 15,000 psi.
Because portland-cement-lime mortar is normally
stronger than the brick, brick masonry laid with this
mortar is stronger than an individual brick unit. The
load-carrying capacity of a wall or column made with
plain lime mortar is less than half that made with
portland-cement-lime mortar. The compressive
working strength of a brick wall or column laid with
plain lime mortar normally ranges from 500 to
For mortar to bond to brick properly, sufficient
water must be present to completely hydrate the
portland cement in the mortar. Bricks sometimes
have high absorption rates, and, if not properly
treated, can suck the water out of the mortar,
preventing complete hydration. Here is a quick field
test to determine brick absorptive qualities. Using a
medicine dropper, place 20 drops of water in a l-inch
circle (about the size of a quarter) on a brick. A brick
that absorbs all the water in less than 1 1/2 minutes
will suck the water out of the mortar when laid. To
correct this condition, thoroughly wet the bricks and
allow time for the surfaces to air-dry before placing.
Good bricklaying procedure depends on good
workmanship and efficiency.
doing the work with the fewest possible motions.
Each motion should have a purpose and should
accomplish a definite result. After learning the
fundamentals, every Builder should develop methods
for achieving maximum efficiency. The work must be
arranged in such a way that the Builder is continually
supplied with brick and mortar. The scaffolding
required must be planned before the work begins. It
must be built in such a way as to cause the least
interference with other crewmembers.
Bricks should always be stacked on planks; they
should never be piled directly on uneven or soft
ground. Do not store bricks on scaffolds or runways.
This does not, however, prohibit placing normal
supplies on scaffolding during actual bricklaying
operations. Except where stacked in sheds, brick
piles should never be more than 7 feet high. When a
pile of brick reaches a height of 4 feet, it must be
tapered back 1 inch in every foot of height above the
4-foot level. The tops of brick piles must be kept
level, and the taper must be maintained during
To efficiently and effectively lay bricks, you must
be familiar with the terms that identify the position of
masonry units and mortar joints in a wall. The
following list, which is referenced to figure 8-32,
provides some of the basic terms you will encounter.
Course One of several continuous, hori-
zontal layers (or rows) of masonry units