Standing seam, valley flashing and capillary action

Old 09-07-20, 09:58 PM
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Standing seam, valley flashing and capillary action

I'm trying to track down leaks in a standing seam roof. Valley flashing has been tucked underneath the standing seam part of the roof for one to two feet and screwed down. Does the seam where the valley flashing and the standing seam part overlap need to be caulked or sealed? I know that capillary action can make water go uphill, but is that a concern in this case?
Old 09-07-20, 10:22 PM
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Typically metal roofs should have a high temp ice and water underlayment, so they should never leak. Caulking the edges of the valley flashing will trap any water that is behind it like a dam and with no way to drain it will cause it to back up. If its leaking, ultimately a poor job of drying the roof in is to blame.

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