- If too much heat is escaping from your attic, the roof surface can rise above the freezing point even when the outside air is below freezing.
- This temperature differential causes some of the rooftop snow to melt, then run down the roof as water.
- When this water hits the cold, unheated eaves area, it freezes.
- As this process of melting and freezing continues it creates a berm of ice all around the edge of the roof.
- When the weather finally warms up enough to melt all the snow on the roof, large amounts of water trickle down, hits the berm of ice, then forms standing pools of water on your shingles.
- Without a constant downward flow, this water seeps in underneath the shingles and drips down into your roof frame.
You’re very lucky that the water hasn’t yet backed up far enough to leak into your home.
The solution is two pronged:
- Increase attic insulation levels
- Boost attic ventilation
Both these changes serve to lower the temperature of the outer roof surface, reducing or eliminating the formation of the ice berm.