In the valley formed by the intersection of two roof slopes forming a re-entering angle, such as that shown in Fig. 456, a strip of lead is laid on the boarding along the intersection of the slopes. The sides are turned up along the boarding for a distance of from 5 to 7 inches, and then dressed over tilting fillets1 fixed parallel to the angle, so as to raise the sides of the adjacent slates.
Sheet zinc is frequently used instead of lead for the flashings of inferior buildings. It is laid nearly in the same manner, but not quite so easily, and does not last so long, especially in bad atmospheres.
Cement flashings, or rather "filletings," are used in the very commonest work. They consist merely of triangular fillets of cement worked into the angles of joints to be protected. Hair mortar is used for filleting in the same way as cement.
Another form of cement flashing is thus constructed: - a row of nails is driven into the wall or chimney an inch or two above the joints to be protected. Bound these is twined tarred oakum. This is then covered with cement forming a projecting ledge, which keeps wet out of the joint.
The various forms of cisterns, and the lead pipes and apparatus connected with them, do not come within the limits of this course, and cannot here be entered upon.
The joints used for lead water pipes are as follows: -
The "Wiped Plumbers' Joint or Round Joint, as shown in elevation at Fig. 480a, and in section at 4806.
1 Sc. Doublings.
To form this joint the ends of both pieces of pipe are made quite circular by forcing into each a wooden tampin. One end is made of a larger diameter and trumpet-shaped, so as to form a socket for the other, the end of which should point in the direction in which the water in the pipe will flow, so as not to cause a check. The outer edges of both ends are rasped to form sharp arrises, so that they will socket together tightly. After fitting both ends should be blacked for about 6 inches in length with "soil." 1 When.dry the ends are shaved, i.e. scraped clean to the length required for the joint, and a little tallow spread over the surface as a flux. Molten solder is then splashed or poured on and rubbed with a cloth to the shape shown at s in Figs. 480a and 4806. Sometimes the socket may be larger, as dotted at f.
The Plumbers' Branch Joint is shown at 480c and 480d.
The Blown Joint or Copper-bit Joint is shown at 480e and 480f
This joint, though sometimes used for lead pipes, is not good workmanship, and is used more by gasfitters and zincworkers than by plumbers.
The Plumbers' Flange Joint is shown at 480g and 480ft. This is useful when a pipe passes through a floor. The solder is sometimes used, even when there is no joint, to support the pipe at this point.