Valley Flashing on Metal Roofs

bill ryan
I am installing an "ABM" corregated metal roof which has overlapping joints (not an interlocking standing seam system) on a new 9/12 roof for a kitchen addition. In addition to ice dam and formed metal flashing under the panels, do you recommend any other type of sealant where the main roof and dormers meet in a valley? The roof has a 20' run (peak to gutters) and is 45' long, I am concerned about ice forming in these valleys in the winter and working it's was up under the corrugations. Earlier in life I did a considerable amount of construction, to include roofing, but this is my first metal roof installation. I try not to use sealants where possible when roofing, but thought there may be standard preformed accessories or recommended sealants in the metal roofing industry to address this. Thank you.
Todd Miller
Isaiah Industries, Inc.
It depends upon the style of valley you're using but oftentimes with the profile of panel you're installing, a butyl tape or sealant would be used. As you know, adhering to manufacturer requirements is critical so I would suggest going back to the roofing manufacturer for this level of installation detail. Thanks so much.

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