Copper Flashings - A Manual - 1925 - Page 22
Fig. 59. One method of flashing a terra-cotta cornice is shown in Fig. 59. The cap flashing on the outside of the balustrade and the flashing above it extending through the wall are both built in as the masonry progresses. Before laying the upper flashing a key is formed by the mason to avoid the chance of a side slip in the balustrade after erection. This key may be formed either by setting two bricks on edge or by the use of concrete; its exact size and location is decided by the design. The copper flashing should be formed closely over the projection in one piece and wide enough so that it can extend entirely through the wall and be turned down on the inside far enough to lap the base flashing at least 4 inches, and turned down outside about ½ inch over the terra cotta to form a drip. The lower cap flashing, also built in with the masonry, turns up against the brick work back of the terra cotta at least 3 inches and down outside on the face of the wall far enough to lap the cornice flashing at least 4 inches. If the lap is to be soldered the distance may be reduced accordingly. The outer edge of the terra-cotta cornice should be so designed as to provide a fastening for the outer edge of the copper base flashing covering the top of the cornice. (A good description of the method of fastening is given in Fig. 63.)
Attention is called to the use of the ⅜-inch thick bronze bar set in the top rail of the balustrade. This bar is continuous on top of the balusters, and if possible should be returned at the ends of the balustrade into the main wall of the building and anchored. The bar is placed on top of the balustrade dowels just before the terra-cotta rail is placed in position.
Fig. 60. A terra-cotta cornice surmounted by a brick parapet-wall faced by terra-cotta and the method of flashing same is shown in in Fig. 60. In this type of construction it is important that the entire top and back of the wall be covered with copper. This will prevent the absorption of moisture by the masonry through the joints of the terra-cotta and brick work and permit cutting down the width of the terra-cotta cap. In designing the terra-cotta cap the upper part of the cap should be made with a roll, as indicated, from 1 to 1½ inches in diameter. The copper is formed over this roll and extended over the top of the cap and down on the inside of the parapet-wall where it is connected to the copper roof by a soldered lock seam. The copper at the back of the parapet should be formed with standing seams and the top with flat seams soldered. The two are joined by a lock seam hammered flat. The top of the terra-cotta cornice should also be covered with copper to protect the joints. The copper may be formed over the upper member of the cornice as shown or the cornice may be designed as shown in Fig. 59 and the copper formed over this step. In either case it is secured in place by screws as described in detail in Fig. 63. After securing the outer edge of the copper as above described the metal is brought back over the top of the cornice and turned up on the masonry. There it is held in place by the copper flashing turned down over it. For cornices with over 2 feet of projection it will be found expedient to form a soldered lock seam halfway across the projection and length-wise of the cornice. The cap flashing begins at the back of the terra-cotta against the brick work and is turned up against the brick work 3 or more inches, then brought outside of the terra-cotta and turned down, lapping the base flashing 4 inches. If the lap is soldered this distance may be reduced accordingly.
Fig. 61. Another method of forming a gutter in a terra-cotta cornice surmounted by a brick parapet-wall faced with terra cotta is shown in Fig. 61. The flashing is continued through the wall beneath the terra-cotta cap to prevent seepage and continues down on the inside of the parapet and is formed with vertical standing seams (see Fig. 60) and connected to the main roof copper by a soldered lock seam. Attention is called to the key formed in the masonry below the terra-cotta cap which is made as described in detail in Fig. 59. The cornice flashing, forming also the gutter-lining, is formed on its outer edge over a terra-cotta roll (as described in detail in Fig. 60) and extends back on the masonry, avoiding all sharp angles, to the brick wall where it is turned up on the wall high enough so that the top will be at least 3 inches above the highest part of the outside of the terra-cotta cornice. For gutters over 2 feet wide a soldered lock seam should be formed longitudinally in the middle of gutter. This seam is secured by cleats nailed to wood strips set in the concrete. (A method of connecting a gutter of this type to the drainage-system is described in Fig. 53.) The cap flashing is laid at the back of the terra-cotta facing of the parapet about 3 inches up on the wall, and extends out under the terra cotta to the outside, where it is turned down 4 inches over the gutter-lining. If this lap is soldered the distance may be reduced accordingly.
Fig. 62. A balcony formed of terra-cotta with a rail of the same material and a window or door opening to it and the method of flashing is shown in Fig. 62. The copper is laid from the outside of the cornice (secured either by screws as illustrated and described in detail in Fig. 63, or over a roll as described in Fig. 60), over a masonry key (described in Fig. 59), and across the floor of the balcony to the main walls, where it is turned up against the masonry and under the terra-cotta and wood sills and up to the back of the wood sill. The introduction of one or more soldered lock seams will be necessary in the floor of the balcony, depending upon the width, and some provision should be made for copper-lined scuppers at such places and of such size as the design of the rail may permit. The bottom of the scuppers should always be about 2 inches above the lowest point of the balcony floor. The flashing of the balcony floor should rise on all sides from 2 to 3 inches above the bottom of these scuppers. Attention is called to the copper water-bar (described in detail in Fig. 11) and the bronze bar in the balustrade rail (described in Fig. 59).
- 22 -