Continue this process until the top of the valley has been reached or until you are satisfied that all broken flashings have been covered.
On a well-nailed wooden-shingled roof, the sheets of flashing may not require nailing, as the pressure of the roofing material should hold them in place, but if the shingles are loose, or if the roofing is of flexible shingles, it will probably be necessary to nail each sheet at a point which will be covered by the sheet above it. If a larger sheet is used more of the flashing will be exposed at the base of the shingle courses (as at F, fig. 4) and the nails in the lower flashing will be completely covered.
If a good material is used the method just described makes a permanent repair and covers the cracks or holes rusted out in the angle of the original flashing.
3. CLEANING OUT AND REPAIRING GUTTERS AND DOWN SPOUTS
Gutters and down spouts require some attention from time to time to keep them in good condition.
Keeping Gutters Clean.
Perhaps the most frequent difficulty arises from an accumulation of leaves, rubbish, and birds' nests in the gutter, which, if not promptly removed, may stop up the opening to the down spout and cause water to back up and flow over the edge. This overflow may cause considerable damage if the gutters are built into the cornice so that the water finds its way down inside the walls of the house. Unsightly streaks and stains on the exterior wall surfaces may also result if the overflow is not stopped. To prevent leaves and other refuse from being washed into the down spout, it is advisable to place a wire basketlike strainer over the gutter outlet. Strainers are usually kept in stock by hardware dealers and are inexpensive. Even though there be no stoppage or overflow, it is advisable to keep gutters clean, since rotting leaves if allowed to remain will cause the metal to corrode and eventually leak. Fine ash and dirt should be removed regularly. Cinders in contact with the metal will set up a corrosive action. When dirt of this kind is removed the gutter should be flushed out with clean water to remove any trace of acid. Conditions such as those mentioned may be avoided if the householder will remember to clean out the gutters occasionally, especially in the autumn after the leaves have fallen.
It is also essential that unusually heavy snow and ice be removed from gutters in order to facilitate roof drainage and to guard against damage to the gutter or its fastenings by the excessive weight of such masses. The life of gutters and down spouts may be extended considerably by occasionally painting them with a good grade of metal paint.