Scaffold or Scaffolding

SCAFFOLD or SCAFFOLDING, properly a platform or stage, particularly one of a temporary character erected for view ing or displaying some spectacle. The most general modern appli cation of the word, however, refers to the temporary frames and platforms erected or suspended at convenient heights to afford easy access to work of construction and repair.

A scaffold, in its simplest form, may be a single plank sup ported by trestles, or it may be the extremely complicated con struction necessary to render every part of a large cathedral or similar building accessible.

Up to a comparatively recent date scaffolds were invariably constructed of timbers bound together with ropes, but now many forms of patent scaffolding and fixing devices are avail able. The more general adoption of steel-framed buildings has contributed largely towards the development of suspended scaf folding. The steel members themselves, supplemented by ladders, provide the only scaffolding necessary in the erection of the frame, and since the steel work is practically completed before the wall filling and facing is commenced, it is more convenient and economical to suspend a single platform—that may extend along the whole face of the building if required, and capable of being raised as the work proceeds—from cantilevers fixed to the top members of the frame, than it is to erect a poled scaffold over the whole face of the building.

Timber Scaffolds.

The ordinary type of timber scaffolding comprises the following:—standards, ledgers, putlogs, braces, scaffold boards and lashings. The standards, ledgers and braces are usually tapering poles (the stripped trunks of young fir trees), about 15 to 35 ft. in length and 31 to 5 in. in diameter at the butt.

The putlogs are of riven birch, 5 to 6 ft. long and 3 in. in section. Scaffold boards are of spruce, 8 to 12 ft. long, 9 in. wide by II in. thick, with the ends bound by hoop iron to obtain strength and security. The ends of the hoop iron should be turned into saw cuts in the edges of the wood to prevent injury to the workmen while handling the boards.

Until recently the lashings were, in nearly every case, made of jute or hemp fibres, white Manila hemp being the best and strongest. Flexible wire cords are now used to a considerable extent for lashings. These cords are about a in. in diameter and are sufficiently long for every form of scaffold junction. They are made of several strands of small gauge wire, one end of the cord being finished with a metal cap or sleeve to prevent the strands from spreading, the other end being turned around a metal eye piece and securely bound or spliced. Scaffold wedges are unnecessary with wire cords.

Chain ties and tightening blocks are frequently used in the place of cord lashings and require less time for fixing. Such a form of scaffold fixing was used in the scaffolding erected for the re construction of Buckingham palace, and in many other important works, and proved to be satisfactory.

Bricklayer's Scaffold.

In erecting a bricklayer's scaffold, the standards are placed upright at a distance of 5 ft. from the face of the wall and from 6 to 9 ft. apart; the lower ends of the standards being held in position by the method best suited to the nature of the site. Thus, the ends may be placed in barrels of earth or sand, they may be placed on a timber sole plate and held in position by nailed fillets; or they may be sunk a foot or two into the ground. The ledgers are fixed horizontally along the inner faces of the standards at vertical intervals of 5 feet. The putlogs are placed 3 or 4 ft. apart, perpendicular to the face of the wall, one end of each putlog resting on the ledger, the other end passing into a recess left, or made, in the wall for that pur pose. The scaffold boards are laid on the putlogs and parallel to the face of the wall. At the position where the end joints between the boards occur, two putlogs are placed a few inches apart to obviate the necessity for lapping the ends of the boards.