Figs A and B are sections through shingle roofs showing methods of flashing the ridge. The flashing is generally formed in 10 ft lengths and is lapped a minimum of 4 in. In Fig A the flashing is nailed to the ridge pole after shingles are in place. In Fig B the flashing is nailed to sheathing after shingle roof is installed and then the flashing is covered by shingles applied end to end across the ridge.

Fig C illustrates use of a metal hip flashing for shingle roofs. Separate pieces of base flashing are installed as each course of shingles is applied. The upper edge of each piece of flashing should extend 2 in. above each course of shingles. The lower edge should be 1/2 in. above the butts of the shingles forming the next course.

The flashings are nailed to the sheathing and the hip pole. The flashing should extend under the shingles a minimum of 4 in.

After shingles are installed, the ridge cap is in stalled using wood screws with water tight washers. This cap, generally fabricated in lengths of 10 ft, should extend onto the shingled roof a minimum of 4 in. and be lapped in the direction of flow at least 4 in.

Fig D illustrates a concealed type hip flashing. After the shingled roof has been installed, a sepa rate shingle covering is made for the hip. Flashing of hip is achieved by adding separate pieces of flashing at each course of shingles. The upper edge of each piece of flashing should extend 2 in. above each course of shingles. The lower edge should be 1/2 in. above the butts of the shingles forming the next course.

The flashing should cover the hip and extend out to within 1/2 in. of the edge of the ridge shingle.

Copper (minimum 16 oz), zinc alloy (minimum 0.027 in.), or painted terne (minimum .015 in. 40 lb coating) is recommended for flashing shown on this plate. Where the expected life of the roof is less than 15 years galvanized steel (minimum 24 ga) may be used but must be painted.