Their economical construction. Economy of operation. The walls. Central supporting posts. Traveling crane supports. Foundation piers. Floor construction. Floor foundations. Roof construction. No gutters usually necessary. Form of gutters, if used. Window construction in monitor roof. Kind of glass preferable. Side window-construction. Window frames. A practical, efficient, and economical building.

For machine shops on level land where little grading or preliminary preparation is necessary, and when the stock, materials, and machinery are all comparatively heavy, one-story shops may be very economically built, according to the plan represented in Fig. 15.

Such a building is not only economical to construct, but also to operate, in that stock and material is easily and cheaply moved from place to place; a traveling crane space is provided; it can be built of any length, and nearly any convenient width; it may be well lighted, no matter in what direction it faces; the form of the timber work renders the hanging of shafting and the putting up of countershafts convenient and economical; it is easy to heat and may be readily ventilated, and the heavy plank roof is free from the trouble of condensation in cold weather.

The walls are of brick, 16 inches thick, and the divisions into window spaces or bays are 10 feet. No pilasters are necessary on a wall of this height, unless very heavy machinery or material is to be employed.

The piers between the windows furnish support for the roof timbers, which are 8 × 16 inches, and placed 10 feet centers, and have a pitch of one half inch to the foot.

The central posts are 10 × 10 inches, and in addition to furnishing support for the inner ends of the roof timbers, they also support the monitor roof structure, whose rafters are cut to the necessary form to give the roof a pitch of one half inch to the foot. To insure rigidity, and to resist wind-pressure, they are braced as shown. If the building is to be for very heavy work the central posts should be 12 × 12 inches.

Along the insides of the central space is run a timber support for the track of the traveling crane. These timbers are bolted to the posts and in addition are supported by brackets, also bolted to the posts. These brackets may be of either hard wood or of cast iron. If the latter, they may have a rib let into the post, for additional strength. If the traveling crane is to handle very heavy loads it will be necessary to support the horizontal timber by auxiliary posts bolted to the main posts and the horizontal timber resting upon their upper ends.

The foundation piers on which the central posts rest should be deep and have a broad base, as they will probably be called upon to sustain much greater weights than the foundation for the side walls, particularly if the shop is designed for heavy work.

The floors should have ample foundation support, and should be constructed by putting down from six to ten inches of broken stone or cinders, well rammed down. Upon this bed floor timbers 4×6 inches may be laid four feet apart, first applying hot tar to their under sides. These having been carefully leveled up, the spaces and all interstices under them should be carefully filled with a concrete of sand of very clean, fine gravel, mixed with hot coal-tar. When this has thoroughly set and hardened, a floor of 3-inch planks may be spiked down. Over this, and at right angles with it, should be laid a 1«-inch hard wood floor, which may be readily renewed when it is worn out. The floor timbers and the top floor should run lengthwise of the building and the 3-inch planks crosswise.

Fig. 15. Machine Shop of one story, Slow-Burning Construction, of Brick and Wood.

A concrete floor may be laid in the central portion, and the above method of plank floor be laid in the side portions.

Where the machinery to be used in the side portions of the building is of moderate weight, and the stock to be handled therein is not particularly heavy, the foundations for the floor need not be of such a substantial character as that described. Probably four or six inches of broken stone or cinders will be quite sufficient for the purpose. The floor planks, too, may be lighter, say 2-inch for the main floor and 1¬ for the top floor, and the floor timbers 4×4 inches.

It is assumed that in all cases the ground has been properly prepared and leveled up before the crushed stone or cinder bed is put down. For this very necessary preparation the reader is referred to the chapter on foundations.

By lessening the depth of the foundation and reducing the thickness of the planks, the expense is considerably reduced and, under the conditions mentioned, the efficiency of the building maintained.

The roof is composed of 3-inch planks, 6 inches wide, with a groove in each edge, and joined by a separate spline, and should be 20 feet long, so as to reach over two spaces between rafters. They should break joints every six planks. Upon these planks is laid either heavy roofing paper, mopped with tar, and then thick roofing tin, or three thicknesses of roofing felt, then coated with hot tar and covered with clean gravel in the usual manner.

No gutters are necessary, the water dripping from the eaves being caught by a strip of concrete 2 feet wide all around the foundation and inclining about 2 inches. This not only takes the water from the roof, but protects the foundation from surface water.

When the building is so located, from its position with reference to other buildings, or to a yard where work is being carried on, that it is not advisable to run roof water off on the ground, gutters may be formed of tin, or better, of galvanized iron, with proper connecting pipes to carry off the water. If the gutters are formed of the roofing felt, tar, and gravel, they will have to be of rather flat sides in order to prevent the tar from running down the conductor pipes when melted by the hot summer weather.

The windows of the monitor roof may be set singly, say 3« feet wide, between the uprights supporting the roof, or they may be made with double sashes in one frame, giving two windows, 3 feet wide each. The top sash should be hung on pivots so as to be opened for ventilation. Ribbed glass will be preferable for these windows, to avoid the glaring light which plain glass would admit upon the erecting floor under the traveling crane.

The side windows may be of two or three sashes, preferably three, the upper sash pivoted and the other two sliding sashes. Ribbed glass should be used in all but the bottom sash, which will very much improve the cheerfulness of the shop by being of clear glass.

The side window frames may be made of the form shown in the back wall, the upper portion being hinged or pivoted for ventilation, and the lower portion divided into two sashes on each side; but the dark shadow cast by the center upright in a double window frame is avoided if we make the window wider and employ a single sash in width.

As will be readily seen, the entire building is designed and constructed with a view of producing a practical, efficient, and commodious structure and one that will be, at the same time, as well adapted to the special uses and purposes for which it is intended as many buildings which are much more elaborate and costly; and still to so construct it as to make it a typical example of slow-burning construction.