In the case of the inside conductors above referred to, cast iron soil pipes may be used; and these, if carried down in a brick wall, should, if possible, be run in interior walls, and at any rate with not less than eight inches of wall between them and the outside air.

Fig. 160. Standing Gutter on Roof.

Fig. 160. Standing Gutter on Roof.

Fig. 161. Cant Board behind Parapet.

Fig. 161. Cant-Board behind Parapet.

The recess is often packed with some non-conducting material. Outside metal conductors are made of tin, zinc, galvanized iron, or copper, the latter being the most desirable and also most expensive. Metal conductors should he made in some form which will permit expansion in case they should become frozen solid. A corrugated round pipe or an octagonal or square pipe is to be preferred. Conductors are usually given an ornamental top of large or small proportions according to situation.

The connection between the conductor and the gutter is usually made by a bent piece of pipe, sometimes a continuation of the conductor, and often a piece of lead pipe, shown in Fig. 162, called a gooseneck. The opening from the gutter to the conductor should be protected by a strainer to prevent leaves, chips, or other substances from choking up the pipe, and the lower end, if connected with a drain, should be properly trapped.

The superintendence of gutters and conductors should cover the construction of the trough, if of wood to be lined, to see that it pitches in the right direction and to the required points. The weight of the metal should be examined, and the manner of securing both gutters and conductors be carefully noted. Tin or iron surfaces which are concealed should be well painted, and all soldering well and faithfully done. The ends and backs of metal gutters must be examined to see that there is a sufficient width of metal to turn up against the wall, or to lie up on the roof, eight to ten inches being as little as it will be safe to allow. All rubbish in the gutters must be removed, and all connections left tight and free from obstructions.

Galvanized Iron Work, The use of galvanized iron for exterior moulded work and bay windows has of late years become an important factor in building construction. Especially is this true of modern fireproof buildings where it is desirable to use no wood in the exterior finish. Belts, cornices, pilasters, door and window finish, and, in fact, all the trimmings of a building, which in former times would have been made of stone or wood, are now, to a great extent, made of galvanized iron or, if not too costly, of copper. The structural treatment of galvanized iron and copper being about the same, it will be necessary to our purpose only to treat of the former, remembering that for large surfaces galvanized iron is the stouter material.

Fig. 162. Gooseneck.

Fig. 162. Gooseneck.