Where the cost is not considered and a good job is desired, it is better to use sheet lead cap flashings in place of tin. They last longer, do not rust, and can be dressed down well to lay tight onto the base flashings. Into the lock C the sheets are attached. After the sheets are laid the seams are flattened down well by means of a heavy mallet, with slightly convex faces, after which the roof is ready for soldering. When a base flashing is required on a roof which abuts against a wall composed of clap boards or shingles as shown in Fig. 204, then, after the last course of tin A has been laid, the flashing B with the lock a is locked into the course A and extends the required distance under the boards D. The flashing should always be painted and allowed to dry before it is placed in position. In the previous figures it was shown how the sheets are edged, both sides being edged right and left. In Fig. 205 is shown what is known as a valley sheet, where the short sides are edged both one way, as shown at a a, and the long sides right and left as s h o w n at b b.
Sheets of this kind are used when the water runs together from two directions as shown by A in Fig.
206. By having the locks a and a turned one way the roof is laid in both directions.
Fig. 207 shows a part plan of a roof and chimney A, around which the flashing B C D F, is to be placed, and explains how the corners C and D are double seamed, whether on a chimney, bulkhead, or any other ject on a roof when t h e water flows in the direction of the arrow F. The first operation is shown at a and the final operation at b. Thus it will be seen that the water flows past the seam and not against it. In laying flat seam roofing especially when copper is used, ance must be made for the expansion and contraction of the sheets.
Care should be taken not to nail directly through the sheet as is shown in WI, Fig. 201. While this method is generally employed in tin roofing, on a good job, as well as on copper roofing, cleats as shown at D in Fig. 208 should be used.
To show how they are used, A and B represent two locked-edged sheets. The lock on the cleat D is locked into the edge of the sheets and nailed into the roof boards at a b c and d, ar as often as required.
In this manner the entire roof can be fastened with cleats without having a nail driven into the sheets, thereby allowing for expansion and contraction of the metal. The closer these cleats are placed, the firmer the roof will be and the better the seams will hold. By using fewer cleats, time may be saved in laying the roof, but double this time is lost when soldering the seams, for the heat of the soldering copper will raise the seams, causing a succession of buckles, which retard soldering and require 10 per cent more solder. When the seams are
nailed or cleated close it lays flat and smooth and the soldering is done with ease and less solder.
When a connection is to be made between metal and stone or terra cotta, the method shown in Fig. 209 is employed. This illus tration shows a stone or terra-cotta cornice A. The heavy line a b c d represents the gutter lining, which is usually made from 20-oz. cold rolled copper. If the cornice A is of stone, the stone cutter cuts a raggle into the top of the cornice A as at B, dove-tail in shape, after which the lining a bed is put in position as shown. Then, being care ful that there is no water or moisture in the raggle B, molten lead is poured into the raggle and after it is cooled it is dressed down well with the caulking chisel and hammer.
By having the dove-tail cut, the lead is secured firmly in position, holding down the edge of the lining and making a tight joint. Should the cornice be of terra cotta this raggle is cut into the clay before it is baked in the ovens. This method of making connection between metal and stone is the same no matter whether a gutter or upright wall is to be flashed. When a flashing between a stone wall and roof is to be made tight, then instead of using molten lead, cakes of lead are cast in molds made for this purpose, about 12 inches long, and these are driven into the raggle B as shown in Fig. 209 at X.
The most important step in roofing is the soldering. The style of soldering copper employed is shown in Fig. 210 and weighs at least 8 pounds to the pair. When rosin is used as a flux, it is also employed in tinning the coppers, but when acid is used as a flux for soldering zinc or galvanized iron, salammoniac is used for tinning the coppers. It will be noticed that the soldering coppers are forged square at the ends, and have a groove filed in one side as shown at A. When the copper is turned upward the groove should be filed toward the lower side within } inch from the corner, so that when the groove is placed upon the seam, as shown in Fig. 211, it acts as a guide to the copper as the latter is drawn along the seam. The groove a being in the position shown, the largest heated surface b rests directly on the seam, "soaking" it thoroughly with solder. As the heat draws the solder between the locks, about 6 pounds of and solder are required for 100 square feet of surface using 14 x 20-incb tin. The use of acid in soldering seams in a tin roof is to be avoided as acid Doming in contact with the bare edges and corners, where the sheets are folded and seamed to gether, will cause rusting. No other soldering flux but good clean rosin should be employed. The same flux (rosin) should be used when soldering copper roofing whose edges, have previously been tinned with rosin.