Copper Flashings - A Manual - 1925 - Page 16
Fig. 43. Two ways of making a water-tight connection between the roofing and an inside iron pipe or leader are shown in Fig. 43. The one on the right shows a method of connecting to a felt-and-gravel or other composition roof, while the one on the left shows the method of connecting to a sheet-copper roof. After the copper drain pan is in place a lead tube (gooseneck) connection to the C. I. pipe is made. This tube is flanged out an inch at its upper end and is soldered to the pan; the lower end is fitted with a brass ferrule which is set into the C. I. pipe and caulked. For the composition roof the copper should extend out on the roof 4 inches beyond the gravel-stop and be incorporated with the roofing. For sheet-copper roofing the connection between the roofing and flashing is made by a lock seam secured to the roof by cleats. This seam is turned in the direction of the flow and soldered. Although the drawing shows one sheet of copper from the gravel-stop and seam to the bottom of the tube, the pan is built up of several pieces. The number and arrangement will vary with each design. To avoid confusion no attempt has been made in the drawing to show the necessary seams.
Fig. 44. For large roof areas on concrete buildings provision must be made for the expansion and contraction of the reinforced-concrete roof slab. This is done by allowing open joints through the concrete roof slab at certain places. These joints must, of course, be recognized in the roofing and an arrangement made so that the roofing will ride with the concrete roof slab and not be broken by the action caused by temperature changes. The condition presented in Fig. 44 shows a tile roof laid on a cement mortar bed over a concrete roof slab with fabric waterproofing between the mortar bed and the concrete slab. The expansion provision for the roofing is made by a band of No. 14 iron painted on both sides with asphaltum and encased in 16-ounce copper. This band is made in lengths convenient for handling; the width should be at least 5½ inches more than the width of the expansion joint in the concrete at the lowest temperature. At each end of the iron band and between the end of the band and the copper a space "B" must be left for expansion. This space should be equal to one-half the width of the expansion joint in the concrete at the lowest temperature plus ¼ inch. The width of the copper, therefore, both on the tile and on the waterproofing fabric will be equal to twice the distance "B" plus 5½ inches. The height is determined by the space required by the mortar bed plus the thickness of the tile. The entire flashing is laid while the fabric waterproofing is being placed or directly afterward, depending on whether it is desired to incorporate the lower flanges of the flashing in the layers of the fabric or place the flashing afterward and cover the flanges with two additional layers of fabric extending out 6 inches on the roof. After the fabric is laid, the mortar bed and the tile are laid. Just before the tile is laid the space between the copper and the cement is filled with mastic-compound and the tile squeezed under the copper and into this compound.
This expansion joint is often made without the iron strip. A copper sheet is shaped roughly as shown in the drawing and is filled with a high-melting-point asphalt. The tile is then set in place. The movement due to temperature changes causes distortion in the flashing strip. The asphalt adjusts itself to take care of this distortion. This method is somewhat cheaper than the one shown but has not the rigidity necessary to resist external wear.
Fig. 45. Another method of connecting a roof surface to an inside leader is shown in Fig. 45. In this drawing the right-hand side shows a composition roof on a wood base and the left-hand side shows a tile roof on a concrete base. The copper tube, before being placed in the cast-iron pipe, is coated heavily with asphaltum. The tube should be secured to the flashing flange on the roof by a soldered lap seam. The lead gooseneck, described in Fig. 43, is also used successfully with this type of outlet. The flashing flange should extend out on the roof a distance at least equal to the diameter of the tube and be incorporated with the roofing. Near the outside edge of the flashing flange a crimp is soldered. In the right-hand example it should be high enough to retain the gravel or slag, and on the left-hand side it should be high enough to finish flush with the top of the tile. The junction of the copper tube and the iron pipe should be carefully caulked, and the opening at the top of the copper tube at the roof provided with a strainer of basket or other design. The strainer has been omitted in the drawing to avoid confusion.
Fig. 46. This drawing is shown primarily to indicate the general type of copper flashing used in this sort of drain connection. The details vary with the design of the connection and the conditions under which it is used. This connection is a patented article and the manufacturers should be consulted for details and the best type to use under a given condition.
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