Carpentry and Contracting

The building industry is today one of our most important and permanent institutions. Every new family unit must find a dwelling place, every new industry must be properly housed in order to do its work without hindrance from the weather. But with this development have come complications never dreamed of by our forefathers. In former years, every carpenter was a builder and he did very well for he confined himself to simple jobs - in fact there were none but simple jobs. There were then no complications with plumbing, gas and water fitting, heating, electric wiring, etc. There were no city ordinances to comply with, no building restrictions to be acquainted with. The laws regarding property rights, labor, etc., were simple, and the question of material was not as complicated.

Today, however, all these things must be considered even if a building is to be erected in a comparatively small town. Most villages have some kind of water system, electricity and gas are almost everywhere, and the house builder demands more artistry in the design and more comforts within the home. Year by year, the practices of our best builders are becoming more standardized, more refined, and more practical. New methods, new tools, and labor-saving ideas are being evolved as new problems of construction present themselves. It therefore behooves every contractor and builder to keep in touch with the progress of the art by possessing handbooks and reference works which will show him the way.

In the preparation of these volumes, the aim has been to create not merely a work which will appeal to the trained expert but one that will commend itself to the beginner and to the self-taught practical man by broadening his knowledge beyond the limits of his experience.

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 Hot - Water 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.

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 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.

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.

Some contractors, whose workmen are required to perform especially skilful labor, figure 15 per cent on all labor and 10 per cent on materials.

Extent of Duplication of Parts. The matter of duplication is an important factor in estimating, as a considerable saving is often made if large quantities of material, either worked or unworked, are required; this is especially true of manufactured parts, such as doors and windows, columns, balustrades, etc. Modern machines are capable of duplication with astonishing rapidity, and workmen can put together similar parts more quickly and cheaply than they can variable members.

Transportation. The distance of the work from the shop of the contractor, or from centers of manufacture, will affect the cost to a marked degree, as much time is consumed in teaming and especially in handling the material a number of times.

If communication between the works and the building site can be established by water, it will usually save considerable expense in freight and handling, with perhaps less risk of damage, and, consequently, less expense for crating and boxing. A careful study should be made of the means of transportation to each different building site from the shop, the office, and the mill, and the data kept for future reference, subject to varying rates and conditions, to change of seasons, and amounts to be transported.

Special Conditions of Each Job. These are some of the more important matters which require preliminary consideration as affecting all estimates, but they are only a small part of the real question involved, as different localities and customs require different treatment, and numerous questions will arise to confront the contractor, all of which may be successfully met by the exercise of care and judgment.

Estimates are formed by many and varying methods, depending upon the degree of accuracy required, the capability of the contractor, and the character of the building. A broad division may be made between approximate estimates and accurate detailed estimates, only the latter of which should be considered when it is the intention actually to carry out the work under a definite contract.

Approximate Methods. Estimating by Cubing. Approximate estimates are obtained with varying degrees of accuracy by several methods, the most convenient and reliable of which is the system of cubing, i.e., the cubical content of the proposed building is ascertained and multiplied by a given price per cubic foot. This rate is obtained by careful comparison of the plans and requirements with similar buildings which have been erected under conditions as nearly as possible like the conditions under which the proposed building can be erected.

Several methods are used to determine the cubical units, depending upon the size and shape of the proposed building. One method is to multiply the square feet in the plan of the building by the distance from half the depth of foundations to half the height of the walls; another system uses the distance from the bottom of the foundation, and another obtains the actual cubical contents. Any of these may be used if the data for comparison is obtained in the same way, but all are subject to important variations which experience and judgment alone will determine. For instance, if the contour of the building is very uneven, with low portions, such as porches and sheds, and high portions, such as towers and cupolas, these must either be omitted from the whole and compared separately, or a lump sum added or subtracted according to the size and elaboration of these members.

Another variation arises in the size of rooms, giving a ratio of partitions and division walls which is not constant; then, too, a large building with many duplicated parts will, of course, require a different rating from a smaller one. The method of estimating by cubing is, therefore, at best approximate, and its degree of accuracy depends largely upon the experience and judgment of the contractor. Even long experience will afford no safeguard against unusual elaboration of interior or exterior, so that cube rates can be applied only to buildings of ordinary character, and comparisons are reliable only between buildings of like description and uses, as the treatment of even the same materials will vary largely in buildings of varying uses.

The height of the building will not increase the cube rate proportionately, unless the internal voids are alike, although it is certain that the higher the building is from the ground, the more time and expense it requires to put the material in place, to say nothing of thicker walls and necessarily heavier construction.

Estimating by the Square. A convenient method of estimating is by the square of one hundred surface feet. This is especially applicable to office buildings, schools, mills, stables, and all buildings where the floors are few in number or similar in plan. For one-story buildings the price per square is taken to include the roof , walls, floor, and foundations, but for buildings of two or more stories the price per square should be taken separately for each floor, the lower floor being price to include the foundations and the top floor to include the roof.

This method of estimating by the square is not so accurate as estimating by cubical contents, but the results are often more convenient and adaptable, because the tabulation of the square area of the various floors may be easily reduced to terms of accommodation for public buildings or shops. For instance, a given floor area in a school house means accommodation for a certain number of pupils; in a church, a certain number of sittings; in factories for the manufacture of staple goods, a certain number of machines and operatives.

Estimating by Units of Accommodation. This unit of accommodation is sometimes carried further, and, by the reverse process, made the basis of another method of estimating the approximate cost of such buildings as the above mentioned, i.e., schools, churches, factories, hospitals, etc. This is also a method by comparison, the known data being supplied by previous experience or calculation, and it is often valuable as a means of determining the approximate cost of buildings necessary to accommodate a given number of individuals or machines, before any definite plans have been drawn.

All of these methods are approximate, with varying degrees of accuracy, and should never be advanced as accurate, or used as the basis of a contract, unless the contractor has had a long and varied experience and feels absolutely certain of his judgment, or unless a proper margin is added for possible variations.

Accurate Method. Estimating by Quantities. The only sure and correct method of estimating is by taking off the actual quantities in detail and carrying out the prices accurately, with the cost of labor, the percentage for profit, and contingencies added.

For this, accurate and complete drawings and specifications are necessary to give the absolute quantity and quality of materials and labor. The various items are then taken off, similar portions grouped, the amount of labor estimated, and a complete and classified schedule prepared and priced at current rates; the cost of transportation, board of men, and any other contingencies noted, a percentage of profit added, and a sum total reached which should be correct if faithfully done.

This, of course, takes considerable time, but is well worth the expense and trouble if a definite contract is to be made.

Preliminary Investigations. In order to estimate to a sufficient degree of accuracy, some things other than the possession of plans and specifications are necessary. A visit to the site should be made, to ascertain the nature of the soil, the levels of the lot, the distance from railroad or wharf, the condition of the roads, and the preparation of the site necessary to receive and dispose of materials. Some knowledge should be obtained of the nature of the subsoil, the presence of ledges or water below the surface which will require especial or costly treatment, etc. Often a deposit of sand will be found upon the site which will not only save carting away the material excavated, but, if of proper quality, may be used for the work. There are many such incidental factors involved, so that a knowledge of existing conditions will be of great advantage to the estimator.

Regarding underground conditions, there is always an element of chance, as the most thorough examination will not always reveal hidden perils. The author knows of a case where a mason had contracted for the building of a sewer, and was in a fair way to make a good profit, when a narrow vein of quicksand was uncovered, to overcome which not only took away all the anticipated profit but caused a severe loss besides.

Ground water is another source of loss and it will be well for the contractor to examine his contract closely, to see to what extent he is to furnish protection from this danger, as a vein of water which may have been temporarily stopped or diverted by the operation of building, will sometimes unexpectedly make its presence known during or after the completion of the work, when it may become a source of great annoyance and expense to the contractor if he has agreed to insure a waterproof job. Numerous illustrations could be given of the danger from unforeseen causes which can at best be only partially obviated by the most careful examination.