How to calculate the final flashing piece

Choose the installation direction first

Label both ends of the wall, then select the end where installation starts. Weather shedding and the specified lap detail control the direction. Mark the piece ID, coverage start, coverage end and cutoff side before forming it. Reversing direction also reverses the taper schedule.

Work a 100-inch run

With 36-inch stock, a 2-inch lock, 1-inch engagement and no first-end allowance, the first panel covers 34 inches and the next covers 33. The final panel must cover the remaining 33 inches, so it remains full width.

For an 84-inch run, the first two panels cover 67 inches. The final coverage is 17 inches; add the 2-inch lock and 1-inch engagement to get a 20-inch stock width. Remove 16 inches from the selected cutoff side.

Final stock width = remaining coverage + lock + engagement
Single-piece run = run + lock + first-end allowance

Transfer the taper at the actual endpoint

For an 84-inch run rising from 10 to 18 inches, the final coverage interval is 67–84 inches. Its profile heights are about 16.381 and 18 inches. A full extra module would go beyond the wall and give the wrong end height.

These are coverage-station heights. Develop the lock, overlap and other folds from the approved profile before turning them into raw blank cut lines. Include any extra height needed for hems or returns in the blank allowance.

Confirm one piece before batching

• Check the physical run and the marked start/cutoff sides.
• Retain the leading connection material; identify which edge is surplus.
• Test the folded lock and developed taper on one sample.
• Match the final endpoint and any peak mark to the wall.
• Use the on-page schedule or CSV to keep stock width separate from coil blank length.