75. The methods employed in laying copper roofs are usually the same as those required for tin roofing, though the flat roof laid with a lap seam is not to be commended. It is weak, and, being soldered and nailed, will not permit sufficient expansion and contraction. Where solder is used, the lock seam with cleats is best. The edges of the sheets and all surfaces with which they come in contact should, before the seaming and folding are done, be thoroughly cleaned with chloride of zinc. When the sheets are in place, mallet them down to the roof. In case the metal is tinned on one side, the folds should be turned so that the tinned surfaces shall face each other. Tinning is resorted to so that the solder may flow or sweat more freely than it will on the copper. The solder used for copper roofs is the same as for tin roofing, but with a flux of sal ammoniac.

The standing seam method of laying should be employed where extra strength and stiffness are required, on very steep-pitched roofs, and on flat surfaces where work without solder is to be carried out.

76. Roll-joint copper roofing is laid in two different ways. In the one the roll is hollow and is secured to the roof by clips or tingles; in the other a solid roll is used, set with a trough or nailed directly to the roof. Fig. 63 shows the hollow roll. The clips or tingles a, a are nailed to the roof before each sheet is laid; against the clips or tingles the edges of the sheets b are turned, and the left-hand sheet is bent over to form the lock c. This joint or lock is seamed and then turned over in a roll, as indicated by the dotted lines and the completed roll d.

77. The trough method is illustrated by Fig. 64. The wood rolls a are 1 1/2 in. X 2 in. The trough b made of copper, in which the rolls are set, is nailed to the roof boards; the sheets c are then bent up to the top of the trough and the edges d of the trough are locked or turned down over them. The cap c is made as indicated, and is sprung tightly over the roll. The other solid roll, shown in Fig. 65, has the roofing plate a bent up and over it, the upper sheet being the last put in place between the rolls as the covering is laid. This, under ordinary circumstances, makes a good roof.

Laying Copper Roofs 291

Fig. 63.

Laying Copper Roofs 292

Fig. 64.

Laying Copper Roofs 293

Fig. 65.

78. To save time and labor, flashings or other vertical jointed work should be soldered, when required, before being taken on the roof. When the sheets are in place, the solder will not flow into the vertical joints; but on the ground, the seams may be laid flat and the solder will readily soak in.

Connections between the flashings of the walls, chimneys, etc. and the gutters should be double locked, and to permit free movement, they should be unsoldered.

79. The gauge, thickness, and weight per superficial foot of copper used for roofing purposes, are given in the following table:

Table 8

Gauge Number.

Thickness in

Decimal Parts of an Inch.

Weight.

Ounces per

Square Foot.

29

.0134

10

27

.0161

12

26

.0188

14

24

.0215

16

23

.0242

18

22

.0269

20