Roofing General Application Data

20. Window caps and all other projections at points where rain water accumulates must be provided with flashings, such flashings must extend a distance of at least 3" (76.2 mm) up the wall behind the sheathing paper.

21. All pipes projecting through roofs shall be flashed and counter flashed. These flashings shall extend 3" (76.2 mm) up under the sheathing paper and not less than 3" (76.2 mm) horizontally. They shall be of sufficient length to cover the shingle/shake course next below the pipe, and to extend up under the straight course above as far as possible without punctured by nails. (Where plumbing vents are carried through roof surfaces, they are generally flashed by the plumber with lead. The lead is carried up on the outside of the pipe and cut off flush with the top of the pipe, and counter flashed with lead extending 4" (101.6 mm) down the outside of the pipe and 2" (50.8 mm) down the inside of the pipe).

Hips and Ridges

22. All shingles/shakes hips and ridges shall be of alternate overlap type applied at the same exposure as filed of roof and with nails long enough to penetrate into sheathing at least 1/2" (12.7 mm) ( 3/4 " (19.05 mm) per Uniform Building code, (UBC).

Valleys

23. Shingles/shakes extend into the valley shall be sawed to the proper miter.

24. Do not break joints into valley.

25. Do not lay shingles or shakes with grain paralell with the centerline of valleys.

26. All valleys shall be installed with shingles/shakes lapping the valley flashing not less than 7" (177.8 mm) on each side.

27. On shingle roofs of less than 1/2 pitch, flashing should extend at least 10" (254 mm) on each side.

28. For shakes, metal valley sheets shall be center-crimped; of 20 " (508 mm) minimum width; underlaid with a strip of No. 15 minimum roofing felt over the sheathing, and coated with a metal paint. When spaced sheathing is used, the felt may be omitted under metal valley sheets.

29. Valley metals that have proved reliable in a particular geographic region should be selected.

Nails and Nailing Shingles/Shakes

30. Nails shall be driven flush but not so that the nail head crushes the wood. They shall be placed approximately 3/4" (19.05 mm) to 1" (25.4 mm) from the side edges of the shingles/shakes and 1 1/2" (38 .1 mm) to 2" (50.8 mm) above the butt line of the following course.

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