Scaffolding. The scaffolding used by bricklayers is thus described by Col. Pasley: - "Consists of - 1. Poles which are usually 20 or 30 ft. long, or even more, and from 6 to 9 inches in extreme diameter at the butt end. 2. Of putlog, which are short poles about 6 ft. long, and seldom more than 4 inches in diameter, but chopped square to prevent them from rolling. The ends are also square, but cut still smaller, so as not to exceed 2 ˝ by 3˝ inches or thereabout, in order that they may be less than the end of a brick. 3. Lashings and wooden wedges; the former of 1˝ inch rope, about 3 fathoms long. 4. Planks of the usual length of 12 or 14 ft., all Iž inches thick, which are generally hooped at the ends to prevent splitting. With these materials the scaffolding for brickwork is put together in the following manner: - First, a line of upright scaffolding poles is erected on each side, parallel to the walls, at the distance of about 5 ft., and at intervals of 8 or 10 ft. apart. They are usually sunk about two feet into the ground at the butt end, and the earth rammed round them. Second, a line of horizontal poles of the same description is lashed and wedged to those upright poles, in the position intended for the first scaffold (or platform). These horizontal poles, which are called " ledgers," are continued all round the building, and where two meet it is usual to make their ends overlap, and to lash them not only to the upright poles but also to each other. The ledgers and poles combine in supporting the superstructure of the scaffold, which is formed by the putlog and the planks. The putlogs have a bearing of about 6 inches in the walls, and are laid in a position that ought to be the place of a heading brick. At the other end they rest on the ledgers; they are usually placed about 5 or 6 ft. apart, excepting between doors and windows, where the piers are sometimes so narrow as to require them to be placed nearer; they cannot of course be introduced where there is any opening without inserting an extra piece of timber across that opening as a beam.

"The planks are placed longitudinally over the putlogs parallel to the wall, and it is common to use four or five planks alongside of each other, which forms a platform 3 or 4 ft. in width. Care should be taken that the planks do not project any distance beyond the putlogs upon which they rest.

" In high buildings, one tier of upright scaffolding poles is seldom sufficient; a second tier is therefore lashed to the first, having an overlap of not less than 10 or 12 ft., where the tops of those of the lower tier agree with the bottoms or butt ends of the upper tier; and in this case it is usual to introduce also diagonal scaffolding poles to connect the whole together, which extend longitudinally at an angle of 45° or thereabouts along the line of upright poles and ledgers, and being lashed to both they stiffen the whole. In addition to these longitudinal braces, transverse struts are sometimes added to prevent the line of scaffolding from separating at top from the wall. These also consist of scaffolding poles, which are made to stand out at bottom at same distance from line of uprights, and to these the principal struts, smaller struts or braces consisting of shorter poles, are occasionally added, which are also fixed in a transverse direction and nearly at right angles to the former, to which they are connected about the middle height of the principal struts." In fig. 294, a a is the wall, b b the upright poles in front of the building, c the "ledgers," d the "putlog," e the planking,//' the braces or struts. The scaffolding used by masons is of a varied character, more or less complicated, according to the nature of the building. Fig. 295 illustrates the elements of scaffolding, consisting of uprights a a, either sunk into the ground or resting upon cross beams or planks - horizontal pieces b b, the upper one of which carries the planking c, forming the platform upon which the workmen stand. In building stone houses the most recent improvement has been the doing away with all external scaffolding, working wholly from the inside; the different heights being reached by gangways or broad planking upon the surface of which cross-pieces are nailed, forming a series of steps or foot-holds; these gangways being supported by the walls and partly by light scaffold timbers. The construction of buildings is now greatly aided by the use of

20 Scaffolding 111

Fig. 294.

20 Scaffolding 112

Fig. 295.