Estimating in Building Construction

120 CHAPTERELEVEN

FIGURE 11.1.Typical Concrete Block

Patterns.

the quantity takeoff, the estimator must keep the amounts

required for the various bonds separate. The types of bonds

that may be required are limited only by the limits of the

designer’s imagination.

The most common shapes of mortar joints are illus-

trated in Figure 11.4. The joints are generally first struck off

flush with the edge of the trowel. Once the mortar has par-

tially set, the tooled joints are molded and compressed with a

rounded or V-shaped joint tool. Some joints are formed with

the edge of the trowel. The raked jointis formed by raking or

scratching out the mortar to a given depth, which is gener-

ally accomplished with a tool made of an adjustable nail

attached to two rollers.

11–5 Concrete Masonry

Concrete masonrycomprises all molded concrete units used

in the construction of a building and includes concrete

brick, hollow and solid block, and decorative types of

block. Historically, many of these units are manufactured

on the local level, and industry standards are not always

followed. There is considerable variation in shapes and

sizes available.

Concrete Block

Concrete block has no complete standard of sizes. The stan-

dard modular face dimensions of the units are 7^5 ⁄ 8 inches

high and 15^5 ⁄ 8 inches long. Thicknesses available are 3, 4, 6,

8, 10, and 12 inches. (These are nominal dimensions;

actual dimensions are 3/8 inch less.) A 3/8-inch mortar joint

provides a face dimension of 8 16 inches; it requires

112.5units per 100 sf of wall. Because there are no industry

standards, it is important to check with local suppliers to

bond.Another popular bond is the stacked bond;this type of
bond will increase labor costs by as much as 50 percent if
used instead of the running bond. Various ashlar patterns
may also be required; these may demand several sizes laid up
to create a certain effect. The estimator must study the draw-
ings, check the specifications, and keep track of the different
bonds that might be required on the project. When doing

FIGURE 11.2.Stone Patterns.