Fig. 49.
“At L you see the gable which has to join the roof of the staircase; and do not forget that stone filletings M must be built into the walls against which roofs abut, forming a weather-moulding above these roofs, to hinder the rain-water from getting in between the slating and the wall. Filletings are most commonly made with mortar or cement, on the roofing itself; but as that is subject to movement, these filletings break away and have to be constantly renewed. Built into the masonry above the slope of the roofing, they cover the junction of the slate or tile with the walls, and, being independent of the roof, they cannot suffer from any giving in the timbers.
“You will draw the roofs to a scale of a quarter of an inch to a foot; I will correct your drawings, and we will give them to the carpenter, in order that he may prepare his timbers as soon as possible. We will figure the scantlings of these timbers. Thus, the blades on the principal rafters should be 8 inches × 7 inches, the collar-clips 3½ inches × 7 inches, the king-posts 7 inches × 7 inches, the tie-beam the same, the main supports 8 inches × 8 inches, the rafters 3 inches × 4 inches, the purlins 8 inches × 8 inches, without sap or flaws.”
“What do you mean by flaws?”
“Depressions; deficiencies of material apparent at the corners when timbers are squared which are rather crooked, and which thereby leave sap visible on these corners and even a hollow place, such as I mark here at A (Fig. [50]). You will be careful not to allow flaws in timbers which the carpenter may employ for the roofs and joists.
Fig. 50.
Fig. 51.
“In considering our floors, I see that for the billiard-room, the dining-room, and the drawing-room, we shall do well to have in each of these apartments two beams to take the joists, on account of the width of bearing, and the partitions which come over these floors. You remember that we deferred this question, and that in the detail (Fig. [42]), and in the section (Fig. [46]), we have supposed the existence of these beams. The joists in these three rooms, instead of bearing from one side wall to the other, will bear from the gable walls on to the beams. But these beams, though cut from the best oak, invariably deflect sooner or later; which, to say the least, looks very bad. We will therefore make them each in two pieces, sawn through in the manner I showed you for lintels, and between the two pieces we will interpose a thin plate of iron. That will enable us to treat the beams like the wall bearers, and fit the joists into their sides, instead of laying them on the top, and consequently avoid a too great projection below the ceiling. Thus (Fig. [51]), having two pieces of timber A, 12 inches × 6 inches, we will put between them a plate of iron ⅛th of an inch thick. We will bolt the whole together at regular intervals as marked at D, and, in the notches C, we will fix the ends of the joists E. A few iron straps will be nailed across to connect these ends one to another, and we shall obtain in this manner perfectly rigid floors. The beams will be supported in their bearings by corbels, and will not go more than six inches into the wall. This then is another detail to be got ready for the carpenter. Mind and see that the ends of the beams within the wall have a coat of red lead, and are enclosed in a box of sheet zinc, No. 14, to prevent the moisture of the wall from penetrating the grain of the wood. Well! that is something done: draw it all out neatly. To-morrow, when I have looked over your drawings, we will send for Jean Godard, and we will go and select the wood in your father’s timber-yard.”