Scarfing, whenever it is practicable, should be made directly over a post, when a simple and inexpensive style, such as is exhibited in Plate 13, will be found sufficiently strong. Indeed, it is hardly possible to find a stronger mode of scarfing than that illustrated in Fig. 1; and yet, being supported by the post, the design is more simple than most of those represented in Plate 12. In this design, the head of the post is framed into a bolster, which ought to be fully equal in size to the timber which it is required to support; in heavy frames it should be about 6 feet long, the braces being framed on a 4 feet run. The bolster is secured to the timber with inch bolts, as represented in the figure. Fig. 1 also illustrates the proper mode of framing braces; the dotted lines show the form of the tenons, and the notchings in the post and the girder represent the facing of the mortices. These are usually notched-in half an inch at least, in order to give all possible support to the toe of the brace; and the measurement, for the length and the run of the braces, must be from the furthest point of the face of the mortice, inside of the notch, and not from the outside of the rough timber. The shoulder of the post is also notched or sized into the bolster an inch, and the bolster is locked into the girder 2 inches; and, if the timber is 12 inches square, the shoulder of the post is 10 inches lower than it would be without any bolster; and the carpenter must, of course, make his brace mortices in the post, accordingly, 10 inches nearer the shoulder than usual. Figs. 2 and 3 are designed to represent a less expensive mode of scarfing on posts. In these plans the tenons extend quite through, and are double-pinned to both timbers, as represented in the plate. This mode is sufficiently strong for scarfing plates and purlin plates. 5 (65) FLOORS IN A BRICK BUILDING. Plate 12, Fig. 1, exhibits the ground plan of one room, 18 feet wide. The joists are 2 by 10, 18 feet long. Trimmer Joists. Those marked A, B, and C, at each side of the fire-place, are called trimmer joists; they are 4 by 10; or they may be made by spiking two common joists together, as represented in the plate. A course of bridging is represented at D, as described in Plate 6. Fig. 2 and Fig. 5 exhibit the method of framing the tenons of the common joists. Fig. 3 shows the mode of framing together the trimmer joists at the corners of the hearth Fig. 4 shows the beveled ends of the joists where they are set into the brick wall. They are beveled in the manner represented, that the springing of the joists may not endanger the wall; and, in case of fire, the joists may burn and fall out without destroying the wall. (66) |