Another point which has been considered is that, notwithstanding the fact that this is a day of specialists, every contractor and builder must be familiar with the specifications for the foundations, framing, interior work, heating, plumbing, wiring, and other specialties entering into the construction of the building. This information is presented in readable form and will be found adequate for the construction of buildings of moderate size. For the details of construction of large buildings of steel and concrete, readers are referred to our more comprehensive reference work entitled "Architecture,, Carpentry, and Building" in ten volumes. The various sections of this work have been prepared especially for home study by acknowledged experts on the subjects and are as free from technical terms as possible. The importance of such practical subjects as Carpentry, Building Superintendence, Estimating, Steam and HotWater Fitting, Drainage and Venting, Blueprint Reading, etc., has been emphasized. The illustrations have been selected with care, and numerous tables and diagrams are introduced wherever possible. It is the hope of the publishers that this reference work will be found of distinct value in its field. ESTIMATING - Percentage · Duplicate Parts-Transportation-Ap- Specification and Its Function-Points of Emphasis in Specification Writing-Specification Writer's Methods of Work: Outlining Main Divisions, Card Catalogues, Specification Reminder, Final Steps- By Eliot N. Jones and O. W. Richardson By F. W. Fitzpatrick Organization, Administration, and Supervision of Building Department -Plans, Fees, Penalties, and Licenses-Fire Limits-Quality of Ma- terials: Tests-Factors of Safety-Loading of Soil-Excavations— Foundations and Footings-Walls, Piers, and Partitions-Boilers, Ovens, and Heating Apparatus-Stove and Smoke Pipes-Chimneys, Flues, and Fireplaces-Mill Construction-Fireproof Construction : General Specifications, Reinforced Concrete Construction, Reinforced Terra Cotta Hollow Tile, Concrete Building Blocks, Steel and Wrought- Iron Construction-Special Building Requirements: Public Buildings, Theaters, Hotels, Plumbing, Heating, Lighting, Hoistways, Well-Holes, Stairways, Doors, Fire Appliances, Standpipes, Fire Extinguishers, For professional standing of authors, see list of Authors and Col- ESTIMATING* PART I INTRODUCTION The ability to estimate may be considered as the dividing line between the journeyman and the master builder for, no matter how skilful a mechanic may become, he can never "hang out his shingle" and invite patronage in his distinctive line of work unless he becomes able to make reliable estimates of material and labor to be furnished. To do this, something more than mere accuracy and quickness in figures or a mastery of mathematics is needed; the estimator must have also experience and judgment, an understanding of the more or less complicated details which go to make up a building, and a knowledge of current prices and discounts in the trade. It is the object of this text to point the way toward the acquirement of such of these essentials as may be imparted by words or figures, that is, to put in condensed form some of the common methods by which estimates are made up, and to point out some of the things which are to be avoided. As prices of labor and materials are constantly shifting with the times and with the location of the job, the figures quoted in this work must be taken only as proportionate, to be used in comparison with known quantities and methods, and not as a basis for making actual estimates. On account of the variableness in price, it is better, in general, to make estimates on the basis of days or hours of labor and of quantities of materials, so that they may be used for comparison in future work, and to this end all estimates should be carefully labeled and filed away for future reference. This should be done whether the bids were successful or otherwise; if a bid is successful, there will arise a good opportunity to compare the estimates of cost of the different items with the actual cost of execution; if a bid The *There is no such a thing as a universal or permanent standard price for anything. Prices vary in different localities at the same time and in the same locality at different times. estimator must therefore acquaint himself with local market conditions in every case. fails to win the job, satisfaction and experience may be gained by noting the items which may have been priced too high or too low. This data will be of great service in preparing future estimates, especially in the comparisons between estimated and actually executed work. GENERAL FACTORS IN ESTIMATING Use of Catalogues and Price Lists. Catalogues and price lists of all standard articles are easily obtained and should be kept at hand, properly indexed, for ready reference, as they contain a great deal of specific information. For close figuring, however, it will not do to rely upon these prices, as the amounts of trade discounts are not always included. These vary greatly from time to time, and often there are two or more discounts-a trade discount, a cash discount, and a variation in discounts made by different merchants—all of which the contractor must be familiar with to obtain bottom prices. Data of this sort should be carefully tabulated for constant reference, in such a form that it may be easily revised and kept, so far as possible, up-to-date. Time and Manner of Payment. The manner and time of payments is a matter to be considered in this connection, so that the contractor can take advantage of cash discounts, which often make a great difference in the cost of certain materials. Determination of Profit. Lump-Sum Method. To the actual price of labor and materials must be added the profit and this will need careful consideration. A common method is to add a lump sum to the estimated cost of labor and materials, this amount varying with locality and customer, with the probable sharpness of competition, and with the circumstances of the contractor. This is a careless method, as it leaves no means for future comparison and no certain knowledge of just what the profits of a given job are. Percentage Method. A better way is to base the profits upon a percentage of the estimated cost. This will vary, in ordinary cases, from 10 to 15 per cent. Ten per cent is the least that should be expected on any work, and is not enough for small contracts of two or three thousand dollars, but for large work, where there is a great duplication of parts and processes, it will generally prove sufficient. |