"All this,"he said,"is a mere trifle indeed - nothing but fancy; we shall have to furnish the details of the woodwork and internal arrangements, and when we come to study them we shall find much to revise. Leave off looking at these interiors for a few minutes, and let us examine the timber-work of the roof. Let us draw it in plan."(Fig. 47).
"The walls A B are the gables which are to support the purlins. We have at C D two cross-walls, which also form gables, and will also receive tie purlins. But the spaces E C are too wide for purlins from E to C. They measure 22 feet between; now the purlins must not have a bearing of more than 13 feet if we would avoid their bending. Intermediate principals are therefore necessary at G H, against the sides of the middle dormers I. The purlins from A to G will not then exceed 13 feet in length, and we shall be able to strengthen them by means of struts from the end gables. From K to L there will be valley-rafters at the penetration of the roofs. Let us first consider the principals G H (Fig. 48).
"The height between the floors of the story in the roof should be 10 feet. We will put two main supports A, fixed into foot-pieces connected by a tie-rod, which will pass under the floor; upon these supports a tie-beam B; then to secure the tie-beam to these supports, clip braces C. On the ends of this tie-beam will rest the purlins D. The blades E will fasten into this tie-beam and into the king-post F. Beneath the second purlins H, it will be necessary to put clips G, forming a collar-beam. The ridge-pole I will be carried by the king-post, with diagonal struts. The other ends of the purlins will rest in the gables. Thus we shall be enabled to fix the rafters which will receive the battens and the slates. These timbers (tie beams, collar-beams, and blades) may pass through the longitudinal wall K, containing the chimney flues, and in turn the roof-timbers will stay the wall, while the wall sup ports and stiffens the roof. As to the middle of the build ing, having the two walls C D, it will suffice to rest the ridge pole L across, and relieve it bearing with two struts M, tenoned into the ends of a beam N, which will prevent their spreading. At the level of the latter we will place the beams a b (see Fig. 47), which will receive the ridge
poles 0 of the cross-roofs. These beams will also be re lieved by struts R. On the ridge-poles 0 will come the 0 meeting of the valley-rafters s (shown in elevation at s). Thus the be everywhere well supported; and, relatively to the surface of the building, we shall use but a small quantity of timber, since we take every pos sible advantage of the support afforded us by the interior walls. The gables will enable us to avoid the necessity of hip-roofs, which are difficult.,t6 contrive and require a good deal of timber. There remains the roof of the staircase. In order that you may understand how to construct it, I am going to draw it for you in perspective. This roof is supported by walls which rise above the cornice of the building, but it penetrates the main roof at x (see Fig. 47). If you examine the drawing (Fig. 39), you will observe that the walls of the staircase leave an angle without any vertical support over the entrance-hall. It will be necessary then to provide a bearing for the hip of the roof which comes over that space. To effect this, we will place on the two wall ends a small principal which shall receive the foot of the hip-rafter v, denoted in Fig. 47. This arrangement is apparent in the perspective drawing (Fig. 49), which gives the square tower of the principal its roof framing. We will raise the oblong newel A of this stairs up to the level of the cornice. Upon the walls we will lay the wall-plates B; then from the three angles to the newel, the foot-pieces C. On the ends, halved together, of these foot-pieces we will erect the two king-posts P, and the three hip-rafters E. The feet of the two king-posts will be connected by the clips F. As to the°13ack hip-rafter G, it will fix into the front of the king-post of the little prin cipal, as I show you at G'; and in order to hinder the principal from being thrust out by this hip-rafter, clips H will connect the head of the king-post of the little principal with the king-post D of the roof. On the angles of the hip-rafters at I, it will be necessary to fix some blocks to carry the ends K of the purlins, which will support the bearing of the rafters.