Figure 42.—Thatch rafter crossings over the under surface of the end principal rafters of the middle section:

1, principal end rafter; 2, thatch rafters; 3, principal purlins; 4, intermediate purlins; 5, curb plate; 6, middle arch; 7, arch of upper series; 8, arch of lower series; 9, wall plate; 10, wall post: a, the thatch rafters cross the principal rafter at right angles in the upper part of the roof. As the addition of thatch rafters proceeds outwards and downwards along the principal rafter, the crossings become more oblique owing to the curve of the curb plate. b, Lower end of principal rafter (1). As the main (3) and intermediate (4) purlins of the middle section are already lashed in position on the principal rafter, the oblique course of the thatch rafters is here and there prevented from reaching the inner edge of the principal rafter. The pointed ends of the thatch rafters are then thrust in under the transverse purlins and the lashing turns can only be made around the thatch rafters at the outer edge of the principal rafter. The middle arch (6) is shown with its end shaped to fit against the end of the wall plate (9) and the curb plate (5). The curb plate is also cut away on its upper part to fit closer to the wall plate.