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Estimated Total

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ESTIMATED TOTAL The estimator is now prepared to group all of his total unit-costs under the following headings: F—Field.


Sub-letting often results in low cost of work, because a sub-contractor who gives all his atten tion to the work can frequently get a small job done to better advantage than a large contractor who has not so much time to devote to details. One contractor can generally manage several sub-contractors on a job much more satisfac torily than several independent contractors can be managed by an engineer or architect.

It is then necessary to decide upon the per centage to be added for overhead charges. These can vary from as low as 4 per cent to as high as 22 per cent, depending upon the kind of organi zation and the distribution of expenses. It will be noted that a number of the items under classi fication III are overhead; and it is well to item ize as many of these as possible in order to make the percentage to be added include as little as possible, and thus be nearer the truth.

P—Profit. The estimator can figure his grand total of cost, to which should be added a percentage for profit. On small work where the risk is large, this should be high; and on large work where the risk is small, it may be as low as 10 per cent when there is competition. The profit should not only take care of the risks of the business that cannot be or are generally not included in the above items; but it should also take care of the compensation to the stockhold ers, or to the contractor himself for his time and skill and risk in organizing the business and keeping it going. Thus, on certain work, 25 per cent or 30 per cent is not an excessive profit.

Hints on Estimates Don't forget that rates of wages arc lowest in dull times and in winter, and highest in boom times and in summer.

Remember that an allowance for discounts is not operative when payment is delayed beyond the time limit.

Repairs on bargain-counter plant may be three times as great as on first-class new equipment.

Depreciation is affected by a multitude of conditions, and estimates of the amount for this item should not assume too high a figure for scrap value.

The interest on plant goes on whether the plant is working or not.

If the non-paying part of a job has to be done first, interest on the loss will run to the end of the contract.

In estimating the cost of transportation, give special attention to the character of available roads, the direction of the proposed traffic, and the time of year.

Insurance against accidents depends upon the riskiness, not to the plant, but to the men.

After making an estimate in detail, lay it aside for a day or two if possible, forget the fig ures, and then go over them again critically.

If someone else is going to carry on the work, take his personality into account in making an estimate of how much his work is going to cost.

Check up an estimate against average con tract prices, selecting particularly contracts where the conditions are well known, and select ing the contract bids from firms of experience in the line of work in question.

Estimated Total

Check over the bidding sheet to see that it compares with the estimate.

A long and big job can be estimated on more safely than a short and small one, since the acci dental conditions on big work are more likely to balance themselves.

It is not wise for the contractor to figure on making money out of lawsuits as he can gener ally make a good deal more money by doing con struction work on a square basis than he can by providing a job for his lawyer.

For trench machine work, from $7.00 to $10.00 a day should ordinarily be added for rental. Also add the cost of the sheeting, plank, and pumping. In estimating the cost of trench ing work, look out for bowlders.

The worst estimate made upon even assumed data is generally a good deal better than guess.

To estimate the quantity of sheeting or of shiplap, calculate the exact surface to be cov ered, deducting openings; then add the following percentages: Sheeting Shiplap For floors 1/7, or 15 per cent 1/6, or 17 per cent For sidewalks 1/6, or 17 per cent 1/5, or 20 per cent For roofs 1/5, or 20 per cent 1/4, or 25 per cent The cost of materials will vary from year to year. A study should be made of the character istic fluctuations in prices, when figuring closely, in order that proper prices of materialg can be determined for some time in advance.

For estimating cost of building work, the reader will also find useful hints and information in the following authorities: Arthur's "Build ing Estimator," Ketchum's "Steel Mill Build ings," and Kidder's "Architect's and Builder's Pocketbook." The prices of hardware may be obtained from "The Iron Age Standard Hard ware List" or the catalogues of standard manu facturers. Current discounts, as well as current prices of material (as lumber, etc.) will be found regularly quoted in the standard trade journals; and different mills issue catalogues giving prices of mill work.