Maintain production history files on every masonry task

By Carolyn Schierhorn

Experienced contractors rarelyhave trouble estimating ma-terial quantities needed for a

job, but estimating labor hourscan be a lot trickier. A multitudeof factors affect productivity, fromunit size, shape, and weight toweather conditions. What's more,all masonry tasks must be accu-rately measured, including the in-stallation of flashing, anchor bolts,movementjoints, and insulation.

"So many people use guess-

estimated into discrete, measur-able tasks," Schiffer explains. "Soif we look at plans for a blockwall requiring #5 rebar at 2 feet,8 inches on center, grouted cells,control joints, anchor bolts at thetop, and saw cuts, as well as theunits themselves, we have a pro-ductivity number for each task-so many lineal feet, cubic feet, orunits per day."

Schiffer converts production fig-ures into "man-day" units, which

work for productivity," observesDan Schiffer of Holt, Mich.-basedSchiffer Mason Contractors Inc.,who has developed masonry esti-mating software and teachesclasses on estimating. For exam-pIe, a contractor may know thata mason can lay 200 standardlightweight block a day but haveno idea how many lineal feet ofsaw cuts a mason can make.

"In our company, we breakdown everything that needs to be

Figure 2. Face brick production curveFigure 1. Concrete masonry production curve

Table 1. Special block production factors

Production

specialblock

Basicproduction

ProductionfactorSpecial block Size Weight

Scored 4x8x166x8x168x8x1610x8x1612x8x16

4x4x168x4x16

4x4x164x8x168x4x168x8x1610x8x16

4x8x166x8x168x8x16

2632394754

1320

1633234655

182227

16315013110590

191176

18414817010788

180172161

.95

.95

.95

.95

.95

.92

.92

.89

.89

.89

.89

.89

.80

.80

.80

15514312510086

176162

1641321529679

144138129

Slump

Split face

accurately, maintain meticulousproduction history records, up-dating your counts weekly.William Pacetti, president ofPacetti Brothers and Trademen'sSoftware in Tinley Park, Ill., pro-vides his foremen with produc-tion charts that include a sketchof each masonry component onthe job. At the end of each day (orweek), the foremen count all theinstalled components, turning in

I the completed production charts

weekly.

Schiffer's foremen are givenforms that show the estimatedaverage man-days for each task.

Sound block

Source: Ref. 1, page 192

equal the number of units or ma-sonry accessories, or amount ofmaterial, a mason will lay on aproject-divided by the averagenumber or amount he could in-stall in a day if he did nothingelse.

For example, let's say a proj-ect requires 60,000 brick; 5,000block; 1,000 cubic feet of grout;and 120 anchor bolts. And the av-erage daily production counts permason are: 600 brick; 180 block;200 cubic feet of grout; and 400anchor bolts. These figures yield60,000+600=100 man-days forbricklaying; 5,000+180=27. 7 man-days for blocklaying; 1,000+200=5man-days for grout placement;and 120+400=0.3 man-days foranchor bolt installation.

Schiffer sums up the total man-days a project requires. Then,

Table 2. Jointingmethod loss factors

" At the end of each day, when

the foreman does his counts, heknows how many man-daysahead or behind he is." Then, ifnecessary, the foreman can en-courage his crew to work harder .If the crew falls way behind,Schiffer might replace it with onebetter-suited to the particularproject.

"Many masonry contractorsdon't know where they stand ona job," Schiffer says. "We knowdaily on every job whether we'vemade or lost money."

The masonry estimating soft-ware packages developed by Schif-fer, Pacetti, and Wendt allow pro-duction figures for every type oftask to be updated easily.

However, to estimate a job thatincludes tasks or materials withwhich he has no experience, Schif-fer must make an educated guessbased upon history records forsimilar situations. If he wins the

Jointing method Lost time (%)

Flush cut (add)ConcaveWeatheredStruckRakedV-tooled

StrippedConvex

2 toS

O

O to 1

O to 2

2to S

2to S

Sto 8

8 to 12

based on how soon he has to fin-ish thejob, he calculates the num-ber of masons and laborers need-ed to complete the job on time.From this figure, he determineshis labor costs.

Likewise, Larry Wendt, presi-dent of Benchmark EstimatingSoftware in Lombard, Ill., tellscontractors at his estimatingseminars to determine separatelythe labor required for the instal-lation of various masonry acces-sories and for tasks such as ma-sonry cleaning. But, he notes, fewmasonry contractors estimateproduction this way.

For example, to cover the costof installing flashing when doneby the masons, some contractorsjust increase the price of the ma-sonry units to be set on the flash-ing. Others charge a flat rate,such as $1 per lineal foot, for allflashing. These methods, accord-ing to Wendt, don't distinguishbetween different types offlash-ing such as copper vs. plastic,and don't take changing job con-ditions into consideration.

"You're comparing apples to or-anges this way ," says Schiffer ."By converting every task intoman-days instead, you compareapples to apples."

Know where you stand on a jobTo estimate future production

Source: Ref. 2, page VII-6

What influences production?At his estimating seminars, Larry Wendt, president of Benchmark Esti-

mating Software in Lombard, Ill., emphasizes that many factors affect ma-son productivity, including:.Crew availability: Some crews may be faster than others

.Experience of foreman

.Expected crew size: Too many masons may get in each other's way

.Masonry unit type: With brick, look closely at initial rate of absorption,texture (affects cleaning), and voids; with block, look at unit weight, thepresence ofhand-holds, and special shapes

.Type of mortar

.Weather conditions: Temperature, humidity, wind speed

.Current economic conditions: During good times, when there is plenty ofwork, production rates go down; rates go up when there are a lot of out-of-work masons

.Job type: Whether industrial, commercial, institutional, residential, orpublicly funded

.Overtime work: Production rates go down with overtime

.Scheduling issues: Material availability, whether project is fast-track

.Location: Crowded site conditions, site accessibility

job, one of his first priorities is todo a time study. He'll go out to thesite with a stopwatch and time amason doing a particular task.

But if the mason lays 30 blocksin an hour, for example, Schifferwon't multiply that number by 8hours to get a daily productionrate. During that hour, the ma-son took no breaks and was onhis best behavior. Multiplying 30by 6.5 hours yields a more accu-rate estimate, Schiffer says.

Reference charts can guideWhen your own records are in-

complete, you can refer to tablesand graphs in masonry estimat-ing books, which are based on theauthors' field experience and re-search. These are no substitutefor experience but can serve asguides until you establish com-plete production history files.

Because unit weight has a sig-nificant impact on productivity,Rynold V. Kolkoski, author ofMasonry Estimating, has createdgraphs relating unit weight toproduction rate (Ref. 1). Figure 1shows a sample concrete blockproduction curve. Note that in-creasing the unit weight from 37

to 52 pounds decreases produc-tion from 137 to 92 units. Figure2 shows a sample face brick pro-duction curve. The average ma-son can lay 560 5.3-pound brickin a day but only 29112.5-poundunits, according Kolkoski's graph.

These production curves arebased on standard units. Any de-parture from the norm adds adegree of difficulty to the task,which can be converted into aproduction factor. Table 1 showsproduction factors for specialblock, including scored, slump,split-face, and sound-dampeningunits. Less than 1, the produc-tion factor is multiplied by thebasic production estimate for thesame-weight standard unit toyield the production rate for spe-cial block.

Similarly, Jerry Pope, authorof Masonry Estimating for a Prof-it, presents production efficiencyloss factors for a variety of condi-tions that impair productivity,such as laying brick over the wall;the number of cuts in the wall;stop-work delays; coffee breakdelays; weather conditions; mate-rial finishes; and raking andpointing. Pope estimates the per-

centage range of time typicallylost; subtracting this range from100% yields the production factorfor the particular task, specialunit, or condition (Ref. 2).

Table 2 shows lost time due totype of jointing method. Concavejoints entail 0% lost time, whichmeans a 100% production factorfor that task. Convex joints, incontrast, result in 8% to 12% losttime, or a production factor of92% to 88%.

The impact of the percentageof saw cut units on lost time isshown in Table 3. Note that if 0%to 5% of the units in a wall arecuts, lost time will range from 3%to 5%. If 40% to 50% of the unitsare cuts, lost time will amount to35% to 40%.

Pope breaks the productionrates down into man-day produc-tion averages for special wall re-inforcing, grout, loose-fill insula-tion, different types of concreteblock, glazed brick, face brick,and stonework, and clay and con-crete pavers. His average esti-mates for concrete block cell fills(grout), for instance, are: for 4-inch block, 55 cell fills per day; 6-inch block, 160 per day; 8-inchblock, 180 per day; 10-inch block,190 per day; and 12-inch block,200 per day.

Estimating production can bedaunting because there are thou-sands of masonry unit types andaccessories and myriad outsidefactors that can have an impact.But reducing each task to man-day units makes estimating easy,Schiffer contends. Just makesure to count accurately everycomponent of a masonry job atleast weekly and update yourproduction history files. n

References1. Aynold V. Kolkoski, Masonry Estimating,1988, The Aberdeen Group, 426 S. West-gate St., Addison, IL 60101.

2. Jerry Pope, Masonry Estimating for aProfit, 1993, Mason Contractors Associa-tion of America, 1550 Spring Ad., OakBrook, IL 60521.

Reprinted from Masonry Construction

@ copyrighted by

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