Fig. 103. Shingling. Toe Hold
In using the chalk line a man for each end is required. The line is chalked and snapped for three courses at a time. The mechanic, after a little practice, is able to keep the butts of the shingles straight and to sight them so that they shall follow the chalk line mark. On long courses a third person may be utilized in chalking and in laying shingles. In chalking, this person holds the line to the roof as sighted by an end man and the snapping is done on each half of the line.
The chalking of a line so as to conserve the chalk is one of the tricks of the trade which must be mastered early. It consists in rotating the chalk about its hemispherical axis while being worked backward and forward along the line, the line being held between the chalk and the ball of the thumb. Otherwise the line would soon sever the chalk.
Fig. 104. Shingling. Toe Holds
Cut nails should be used in preference to wire nails because of their greater rust-resisting quality. Dry shingles should not be laid tight together, ⅛ inch between is not unusual with dry shingles. It is best to split shingles over 10 inches wide before laying them. Each shingle should have at least two nails, the average is two nails for every four to six inches of shingle.
Scaffolding for roof work, or toe hold, is usually constructed by nailing shingles to 2" × 4" as shown in Figs. [103] and [104]. Other forms are equally common. Apparently the holes left by the nails used to fasten the toe hold to the roof would cause a leak in the roof. To avoid any such danger, tho such danger is slight because of the swelling of the wood fiber upon the application of moisture, the shingles having such holes are driven down the roof slightly by striking their surfaces a glancing stroke.
54. Shingling Hips and Valleys; Flashing; Saddle or Comb Boards.—Hip and valley shingles are usually sawed to shape before being taken to the roof, the face cut being the same as that used across the face of the roof boards and plancher members intersecting about a corner of a hipped roof where plancher lies in the plane of the roof. The cut across the edge of such shingles is made square to the face.
