OF BUILDING CONSTRUCTION DATA FOR ARCHITECTS, DESIGNING AND CONSTRUCTING VOLUME II COMPILED BY A STAFF EDITORS-IN-CHIEF GEORGE A. HOOL, S. B. CONSULTING ENGINEER, MADISON, WISCONSIN AND NATHAN C. JOHNSON, M.M.E. CONSULTING ENGINEER, NEW YORK CITY FIRST EDITION MCGRAW-HILL BOOK COMPANY, INC. It can be said that modern construction methods owe their supremacy to the mistakes of the past and an equally plausible assumption follows that the mistakes of the present will be of similar if not greater assistance to the builder of the future. A recognition of this fact by many of our representative builders has inclined them, in an earnest effort to profit by their own errors, to undertake a more serious and systematic study of the problems coming before them than they were wont to make in the past. Feature by feature, each feasible scheme has been taken up and separately analyzed; every branch of industry has been called upon for that which would seem to assist or be of benefit and every science has been enlisted for that which would be helpful, until today there stands a profession in all that the name implies to supplant what was only a trade of yesterday. The first result of such serious study has been a general systematizing of the essential forces and efforts, both as applied through the office in preliminary preparation as well as in actual field operations. System implies control, and this is now obtained through the assistance of two highly important documents: (1) the "time schedule;" and (2) the "working estimate." 1. The Time Schedule. Every building operation before reaching the construction stage should be placed on a definite time schedule, with predetermined dates for the arrival and departure of each individual trade that will enter into its construction. In form it may not be unlike the railroad folder of common usage. A more forcible resemblance may perhaps be found in the discovery that it is equally as destructive to the progress of a building to assign two conflicting trades to the same period as would obtain were two trains to attempt the same stretch of track concurrently. 1a. Elements of the Time Schedule. A properly prepared building schedule will assign to each trade on the operation four definite dates: 1. The date on which subcontracts or purchase orders should be placed in order that the materials involved may be properly and economically prepared and deliveries synchronized to keep pace with the leading trade. On a well-analyzed operation, such a thing as waiting for materials is quite inexcusable; not only will the continuity of the trades be disturbed, with consequent hardship to other departments and lines not to blame, but more often than not, a permanent delay to the building's completion will ensue. This directly affects the owner's interest, and on many enterprises, where the investment assumes vast proportions as the date of completion approaches, even so little as a day's delay may be a matter of serious financial loss. Equally so, it is important not to crowd a job with materials before the operation is ready. To do so means additional expense of rehandling and temporary protection, to say nothing of the handicap placed on other trades by causing them to work over and around stored materials. 2. The latest date on which all information inclusive of designs, scale details, and approved shop drawings must be in the hands of the subcontractors or shop, in order that they may intelligently prepare or fabricate the materials and meet promised delivery. With the importance of this date recognized by the architect or designing engineer, little or no difficulty should be experienced in adherence thereto. On the other hand, without this very close cooperation, many serious set-backs will creep into the building operation and constant watchfulness may be required on the part of the builder to protect the schedule at this point. 3. The date on which actual field work at the building should commence. Here again, delays are dangerous. The failure of one trade to take its appointed place at the time designated will either throw back all succeeding trades a corresponding period or will result in the confusion of two or more trades trying to operate in the same space, until the delinquent one has speeded up to resume his normal station. While the exact sequence in which the various trades should be brought upon the work is in a few instances debatable, their position as a rule is generally predetermined by the relation one bears to the other. When this relationship is not clearly defined, such as between |