This section is from the book "A Treatise On Architecture And Building Construction Vol3: Stair Building, Ornamental Ironwork, Roofing, Sheet-Metal Work, Electric-Light Wiring And Bellwork", by The Colliery Engineer Co.. Also available from Amazon: A Treatise On Architecture And Building Construction.
Fig. 7 shows the parts and joints in a sheet-metal cornice as ordinarily constructed in small sections on a brick wall. The foot molding a is fastened to and supported by a board and wooden lookouts, the lower member being allowed to hang down below the raglet or groove which runs along the joint of the brickwork at the underside of the lookouts. The top of the foot molding enters the raglet in the next joint above. The paneled frieze b is made up in one piece between the trusses or brackets c, the edges being doubled over and secured into raglets as shown. The modillion course, which generally includes the small moldings above and below the plain surface from which the modillions project, is attached to the brickwork in a similar manner and is secured in place with a long, narrow, metallic wedge. If the cornice is erected while the walls are being built, the upper flange of each piece is usually bent over far enough to be safely bedded in; the lower edge of the sheet above being bent over and pushed into the same joint as the work progresses. The soffit e may be bent up out of the same piece with the bracket molding. The drawing, however, shows it separate, and secured to the board lining f.
The crown molding g is bent over the top of the roof boards, leaving an edge turned up as at h for easy connection to the sheet metal of the roof. The lower edge of the crown molding should be made to form a drip, as shown, and should be securely nailed to f.
The brackets and trusses which are hollow and built up from stamped sheet metal are riveted and soldered in position. It is difficult, however, to properly attach them when the cornice is put up in sections, as shown, so it is advisable to have these projections riveted and soldered on before the cornice is put up. In the construction of cornices, particular care must be taken to avoid pockets in which water may accumulate. If there is any suspicion of a water-tight pocket, a small hole should be punched at the lowest point to allow any water to drain out. If this is not attended to, these pockets may fill up with water, freeze, and burst.
15. Another plan for securing cornices against brick walls is to spike boards against the face of the walls, plant the cornice on top of the boards, and nail it in place. The former method, however, is preferable, not only because the nails must show by the latter method, but chiefly because the boards will warp and the cornice will consequently become distorted and loosened.
The cornice work shown in Fig. 7 is attached to a brick building with a flat roof. The roof pitches down to the back of the building and the conductor pipes, of course, are in the rear. When the roof pitches in the direction of the cornice, a gutter is usually formed at the back of the crown molding.