Metal Roof Ice Dam Help
Hello GBA community,
I recently built a new home following the “pretty good house” principles in CO (zone 5). Much of the build was done with info learned from this site, and everything turned out awesome with one exception – minor ice dams. My roof assembly is a standard vented assembly with dark red metal instead of shingles. I’ve got continuous soffit venting and ridge venting. The attic is a sealed attic with R-70 blown cellulose. I have zero penetrations in my ceiling for can lights and exactly 2 electric boxes for ceiling fans, both of which were air sealed meticulously before drywall, so I’m confident I don’t have interior air leaking into my attic.
The ice damming only seems to happen on days when the temperature is sub-freezing but the sun is shining bright – on cloudy, sub-freezing days I have no melting, thus ice dams never form.
Is the problem likely from not enough air flow exiting the ridge vent, too much cold air entering the soffits, both, neither?….Any advice is appreciated.
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