Estimating in Building Construction

Labor 55

EXAMPLE 7-2 LABOR HOURS

Type of work—8'' 8'' 16'' Concrete Masonry Units—

Decorative

Historical productivity rate—0.1 labor hours per sf

Productivity factor—1.1

Crew—three masons and two helpers

Labor hours 1,000 sf0.10 labor hours per sf

100 labor hours

Adjusted labor hours 100 labor hours 1.1

110 labor hours

Sixty percent (3/5) of the hours will be performed by masons and
40 percent (2/5) will be performed by their helpers.

Mason labor hours 0.60 110 labor hours
66 labor hours
Mason helper labor hours 0.40 110 labor hours
44 labor hours 
Another method of determining the productivity rate is
cycle time analysis, which is used when the work is performed
in a repeatable cycle. An example of a cycle is a truck hauling
earthen materials from the borrow pit to the job site and
returning to the borrow pit to make a second trip. Cycle time
analysis is used extensively in excavation estimating. Cycle
time analysis is performed by timing a number of cycles, ide-
ally at least 30. Using the average cycle time (in minutes), the
productivity rate is calculated using Formula 7-4. The average
cycle time is determined by summing the cycle time and by
dividing the sum by the number of observations. The produc-
tivity factor is the same as the productivity factor used in
Formula 7-3. The crew size is the number of people in the crew
and determines the number of labor hours per clock hour. The
system efficiency takes into account that workers seldom work
a full 60 minutes per hour. Typical system efficiencies range
from 30 to 50 minutes per hour. The quantity per cycle is the
number of units of work produced by one cycle.

Productivity Rate Formula 7-4

EXAMPLE 7-3 PRODUCTIVITY RATE USING
CYCLE TIME
Type of work—Hauling materials from the borrow pit
Average cycle time—35 minutes
Truck capacity—17 tons
Crew—One driver
Productivity factor—0.95
System efficiency—45 minutes per hour

Productivity rate 0.0435 labor hours per ton 

Productivity rate

35 minutes0.95 1

45 minutes per hour 17 tons



Average cycle timeProductivity factorCrew size

System efficiencyQuantity per cycle

Productivity rate

When the work is performed linearly (such as paving or

striping a road, placing a concrete curb using slip-forming

machine, or grading a road), the rate of progress may be used

to determine the productivity rate. The productivity rate is

calculated using Formula 7-5. The quantity is the quantity of

work to be performed; in the case of placing concrete curb, it

would be the length (in feet) of the curb to be placed with the

slip-forming machine. The rate of progress is the number of

units of work that can be performed by the crew each minute

when they are performing the work. In the case of placing a

concrete curb, the rate of progress would be the number of

feet of curb that is placed in one minute. The travel time is

the time (in minutes) that the equipment is not working

because it is being moved from one section of work to

another section of work. In the case of placing the concrete

curb, sections of curb will be left out where there is a tight

radius or a driveway approach. The travel time would be the

time it takes to move the equipment forward through the

driveway approaches and sections where the curb is not being

placed by the machine. The crew size is the number of people

in the crew and determines the number of labor hours per

clock hour. The system efficiency takes into account that

workers seldom work a full 60 minutes per hour. Typical sys-

tem efficiencies range from 30 to 50 minutes per hour.

Productivity Rate Formula 7-5

EXAMPLE 7-4 PRODUCTIVITY RATE USING RATE

OF PROGRESS

Type of work—Slip forming concrete curb

Quantity—2,200

Number of approaches—30 each @ 3 minutes each

Number of curves—5 each @ 5 minutes each

Rate of progress—3per minute

Crew—One operator and two helpers

Productivity factor—0.95

System efficiency—45 minutes per hour



When company data are not available, data from published

sources can be used. Figure 7.1 shows the productivity and

costs for concrete unit masonry from R.S. Means Building

Construction Cost Data. From Figure 7.1, we see that the

Productivity rate0.0257 labor hours per foot

Productivity rate

a

2,200

3 feet per minute

115 minutesb 3

45 minutes per hour2,200

115 minutes

Travel time 30 3 minutes 5 5 minutes



a

Quantity

Rate of progress

Travel timebCrew size

System efficiencyQuantity

Productivity rate