This section is from the book "Cyclopedia Of Architecture, Carpentry, And Building", by James C. et al. Also available from Amazon: Cyclopedia Of Architecture, Carpentry And Building.
There is another form of roofing known as metal slates and shingles, pressed in various geometrical designs with water-tight lock attachments so that no solder is required in laying the roof. Fig. 1S9 shows the general shape of these metal shingles which are made from tin, galvanized iron, and copper, the dots a a a a representing the holes for nailing to the wood sheathing. In Fig. 190, A represents the side lock, showing the first operation in laying the metal slate or shingle on a roof, a representing the nail. B, in the same figure, shows the metal slate or shingle in position covering the nail b, the valley c of the bottom slate allowing the water, if any, to flow over the next lower slate as in A in Fig. 189.
In Fig. 191 is shown the bottom slate A covered by the top slate B, the ridges a a a keeping the water from backing up. Fig. 192 shows the style of roof on which these shingles are employed, that is, on steep roofs. Note the construction of the ridge roll, A and B in Fig. 192, which is first nailed in position at a a etc., after which the shingles B are slipped under the lock c. Fig. 193 shows a roll hip covering which is laid from the top downward, the lower end of the hip having a projection piece for nailing at a, over which the top end of the next piece is inserted, thus covering and concealing the nails. Fig. 194 represents a perspective view of a valley with metal slates, showing how the slates A are locked to the fold in the valley B. There are many other forms of metal shingles, but the shapes shown herewith are known as the