Images of snow covered roofs with icicles depict the typical winter scene. While many see the icicles as a thing of beauty they are the sign of a problem
The formation of icicles is part of what’s called an ice dam. Ice damming occurs when the roof is covered with snow and the underside of the roof gets warm enough to melt the snow. The water under the snow runs down the roof and when it gets out to the cold air it freezes again and turns in to icicles. When the water can’t get to the roof edge it can back up under shingles or even under the sheathing and into the attic and walls.
The cause of the ice dam is warm air and heat that escapes into the attic. So it’s a sign your loosing money. Air sealing the attic and increasing insulation are two of the more common things that could be done. Sometimes attic ventilation might be needed but the other two things should be looked at first because attic ventilation won’t solve heat loss and can sometimes make the situation worse.
When I’m doing an Energy Audit in Reno I see ice dams often but when I go up to the Lake Tahoe area they are more common and it’s even more important to take care of the situation. If you see large icicles call in an Energy Auditor like me to help diagnose the problem and assist in a solution that will not only help control the ice damning, but also save energy and money.
Large Ice Damn due to heat loss. No air barrier and holes cause loss.