Shingling. The reason for placing cornice before base or window frames, etc., is to allow the workmen to work inside should inclement weather overtake building operations at any time. Shingling, therefore, will follow cornice work.
Fig. 101. Spliced Corner Boards and Moulding.
The amount of shingle to be exposed to the weather will depend in general upon the pitch of the roof. In no case should this exposure exceed 5 inches. The shingle most used is 16 inches long, and each shingle should lap two courses beneath it. The usual amount of lay is from 4" to 4¾", by quarters. When nearing the ridge or comb of a roof in shingling, the dimensions used on the main body of the roof should be increased or decreased so as to make the final layer show under the comb or ridge or saddle boards properly. The worker should begin such calculations when within about four or five feet of the ridge so that changes of exposure of the different layers may not be noticeable and so that the line of shingle butts may be kept parallel with the ridge.
Fig. 102. Beginning Course.
The first layer of shingles should be a double one with joints properly broken, and with the butts projecting over the crown moulding about 1½" to 2". Lay the shingles at the gables first, then at intervals of about ten feet. Stretch a chalk line between these fastening it to the butts by shingle nails driven into the butts, Fig. 102.
The remaining courses may be laid by means of a straight-edge or by means of a chalk line. Both practices have ardent advocates. Where a straight-edge is used, it is usually a piece of lap siding or clapboard, and is held in place by being lightly tacked.
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.
Fig. 103. Shingling. Toe Hold.
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.
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.
Fig. 104. Shingling. Toe Holds.
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" x4" 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.