Apprentice question
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Reverse-lapped flashing sends water behind the wall protection. Stop and correct the shingle-lap sequence so water drains out, not into the wall.
['Exterior flashing works like shingles: upper layers must drain onto lower layers. If the head flashing is placed on the wrong side of the weather barrier, water can run behind the flashing into the wall cavity.', 'Stop covering work, expose the head condition, and coordinate the correct lapping detail with the GC/envelope trade. Usually the top leg must be integrated behind the weather barrier or approved flashing tape system, with side/end detailing per the project envelope detail.']
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