How wide step flashing should be is specified by building codes and shingle manufacturer installation instructions to ensure adequate coverage and watertight performance. Standard step flashing pieces are typically 7 to 10 inches wide and 7 to 10 inches long, bent into an L-shape with one leg going up the wall and one leg onto the roof deck. Common sizes are 8 inches by 8 inches or 10 inches by 7 inches. The horizontal leg that extends onto the roof deck should be at least 4 inches wide to ensure it is properly covered by shingles and provides adequate overlap onto the deck, with many professionals preferring 5 to 6 inches for extra protection. The vertical leg that goes up the wall should be at least 4 to 6 inches high to prevent water from running over the top, with 5 inches being typical. When interwoven with shingles, each shingle course should cover the step flashing piece below, with the shingle overlapping the flashing by at least 1 inch. Each piece of step flashing should overlap the piece below by at least 2 inches, with 3 inches preferred. For wider coverage in areas with heavy water flow, wider flashing may be used, but it must still be installed as individual step pieces, not continuous L-flashing, to accommodate movement. Always check local code and manufacturer specs for minimum width requirements.
1 votes
Marked as accepted