Joints.

There are two types of joints used in connecting two strips of roofing such as "b" and "c" in Fig. 21. One is the self-capping standing-seam joint, and the other is Fig. 22 the roll-and-cap joint.

Standing-Seam Joints.

Standing-seam joints may be single-lock or double-lock seams. A single-lock standing-seam joint is illustrated in Figs. 22, 23, and 24, in which the successive processes in making this joint are shown. Cleats "a", Fig. 22, are nailed to the sheathing, at 12-inch intervals, against the upturned flange "b" of a strip of roofing previously laid. The cleats hold the roofing firmly in place, the ends of the cleats being bent down over the upturned edge of the sheet. The cleat should be long enough to reach nearly or quite down to the roof, as at "c". The next strip of roofing is placed over the cleat and against the first strip as shown in Fig. 23. The edge is bent up 1 inch, while the edge of the first strip is bent up 1½ inches. The top of the cleat a and the top of the flange "b" are then bent down over the flange "d" as shown in Fig. 24. The top of this seam is about 1 inch above the roof surface. The seam is then pressed together tightly.