Estimating in Building Construction

Masonry 123

When estimating the quantities of concrete masonry,
use the exact dimensions shown. Corners should only be
taken once, and deductions should be made for all open-
ings in excess of 10 sf. This area is then converted to units,
and to this quantity an allowance for waste and breakage
must be added.
While performing the takeoff, the estimator should
note how much cutting of masonry units will be required.
Cutting of the units is expensive and should be anticipated.

Units per square foot1.125 blocks per sf

Units per square foot

144

8 –  16 –

In working up the quantity takeoff, the estimator must

separate masonry according to

1. Size of the units


2. Shape of the units


3. Colors of the units


4. Type of bond (pattern)


5. Shape of the mortar joints


6. Colors of the mortar joints


7. Any other special requirements (such as fire rating)
   In this manner, it is possible to make the estimate as
   accurate as possible. For mortar requirements, refer to
   Figure 11.7 and Section 11–16.

FIGURE 11.7.Mortar Mixes to Mix 1 cf of Mortar.

EXAMPLE 11-1 CONCRETE BLOCK

Determine the quantity of concrete block required for the west wall
of the small commercial building found in Appendix A. Figures 11.8
and 11.9 are excerpts from those drawings and are helpful in deter-
mining the quantity of concrete block.

FIGURE 11.8. Building Floor Plan.

Gross wall area (sf )15.33¿59.25¿ 908 sf

Gross wall area (sf ) 15 ¿ 4 –  59 ¿ 3 –

West wall length 60 ¿ 0 –  9 – (both end brick ledge) 59 ¿ 3 –

Wall height for concrete block 16 ¿ 2 –  10 –  15 ¿ 4 –