Scaffold or Scaffolding

Scaffolds of this type should always have diagonal braces fixed across the faces of the standards to avoid risk of failure by side racking, and the scaffold must be prevented from falling away from the face of the wall by ties or bridles through the window openings. The third possible cause of failure, the buckling of the standards, is guarded against in scaffolds supporting heavy loads by having the whole or lower part of the scaffold "double poled." All scaffolds should have guard planks and guard rails fixed to the outer standards.

As the work is carried up the boarding and many of the put logs are removed to the stage above, some putlogs, however, being left tied to the lower ledgers to stiffen the scaffold. In the case of thick walls a scaffold is required inside as well as outside the building, and when this is the case the two structures are tied together and stiffened by short connecting poles through the window and door openings.

Mason's Scaffold.

The mason requires an independent scaf fold. He may not rest the inner ends of his putlogs in the wall as the bricklayer does, for this would disfigure the stonework, hence another and parallel framework of standards and ledgers is placed within a few inches of the wall-face upon which to sup port them. The two portions are tied together with cross braces, and the whole of the timbering is made capable of taking heavier weights than are required in the case of the bricklayer.

Masons' scaffolds upon which banker work is done are usually of sawn material bolted together; the arrangement of the rectan gular members corresponding to that in the ordinary type of scaffold.

Metal or Tubular Scaffold.

This type of scaffolding was used during the process of erection of Bush house, Aldwych, Devonshire house, Piccadilly and many other important buildings in London and the provinces, and must now be noticed in any reference work on scaffolding.

The special advantages claimed for tubular scaffolding are :—It is easily transported; since 12 feet is the maximum length of any member a great quantity may be stored in an ordinary truck. Its strength is beyond question, it is fireproof and practically inde structible. It is easily introduced into narrow or tortuous en trances, and may be erected with great rapidity and little labour. It is not affected by climatic conditions, is neat and compact when erected and is light and efficient for slung scaffolds.

Tubular scaffolding consists of sections of steel tubes, about 2 in. in diameter and of various lengths, with various forms of clips and couplings, base plates and patent putlogs.

The putlogs are of oak reinforced with steel, the steel projecting beyond the wood to allow it to be inserted and wedged into the brickwork joints when necessary. Thus putlog holes are not required to be left or made in the wall surfaces. The standards are not placed more than 8 feet apart for ordinary scaffolds, and not more than 6 feet apart for masons' scaffolds. The diagonal bracing is fixed by special swivel couplers.

Suspended Scaffolding.

Where the nature of the building will permit of its use suspended scaffolding has many very impor tant advantages. Thus, in high steel framed buildings the lower floors may be occupied before the upper ones are completed. The scaffold platform may be kept at the position in which the work is always at bench height. The space immediately below the scaffold is clear of obstructions. The scaffold platform is flexible and its height may be varied along its length, within certain limits, to suit special conditions.

This form of scaffolding was used in Adelaide House, London, E.C. ; the Lewis Building, Birmingham ; Messrs. C. and A. Modes Ltd., Liverpool, and many other equally large and important buildings, and has proved to be safe, convenient and economical. The complete scaffold is made up of a number of units or sections.

Each section has a machine or winch at each corner, the sup porting cables being wound or unwound about the machine drum by a device specially designed to ensure safety while raising or lowering the platform.

Gantries.

"Gantry" is the term applied to a staging of squared timber used for the easy transmission of heavy material. The name has however, come. to be used generally for strong stagings of squared timber whether used for moving loads or not. Taking the general meaning of the term, gantries may be divided into three classes: (I) Gantries supporting a traveller; (2) Travelling gantries, in which the whole stage moves along rails placed on the ground: (3) Elevated platforms which serve as a base upon which to erect pole scaffolding.