Ice Dams in Gutters – The Minneapolis Ice Dam Myth
Wednesday, December 31st, 2014
In 2011, Ice Dam Company owner Steve Kuhl wrote a nationally published article about ice dams for the Journal of Light Construction. One of the topics that receieved the most attention was the notion that gutters have nothing to do with ice dams. Here is a deeper look at that assertion.
There is a great deal of confusion and misinformation about the relationship between gutters and ice dams. Many people are under the misconception that gutters cause ice dams or that gutters filled with ice can cause water to back up into homes. Neither is true. Nor do gutters amplify the negative effects of ice dams in terms of the likelihood or severity of leaks into a home.
We know that ice dams occure when:
1. Escaped heat from the inside of the home warms the roof deck.
2. This melts the snow on the roof, resulting in water that runs down to a cold, unheated area of the eave.
3. That water freezes, forming ice. After many cycles that ice piles up to form an ice dam.
Study the illustrations below. These are identical eave designs, one with gutters, the other without. The Area B in the diagrams below is referred to as the ‘cold edge’ of the eave because heat from the interior of the home doesn’t travel far enough to raise the temperatures above 32 degrees in this zone. Fact one: whether or not a home has gutters, the cold edge of the eave will still exist and this is where ice dams form. Fact two: leaks from ice dams occur in Area A, at the top edge of the ice dam where water–with nowhere else to go–is forced up under the roofing material and into the home. Another way to look at it is this. If the home in Figure 2 had bad leaks inside, those leaks would not be eliminated whatsoever if we took a chainsaw and cut off the gutters along the red dashed line (C). Gutters are irrelevant in the formation of ice dams. Gutters being full of debris is likewise irrelevant in terms of ice dams. End of story.
None of this is to suggest that ice in gutters is a harmless situation. We have seen many gutters damaged or destroyed by ice dams and that is a problem most homeowners would like to avoid. The point here is that all else held equal, if a home is likely to get ice dams the addition or deletion of gutters will be of no consequence to the formation or severity of said ice dams.
Ice dams can cause all sorts of damage. Below is a client of ours who had significant damage to her gutters and aluminum soffits from ice dams. Kuhl’s Contracting, our sister company, is one of the best companies in Minneapolis when it comes to repairing ice dam damage and ice dam prevention. Kuhl’s Contracting also installs more ice dam heat cables than any company in Minnesota. Of course, heat cables and heat tape are not a permanent solution for ice dams in Minnesota. Click here to see a Kuhl Case Study that examines one such approach to ice dam prevention using enhanced home insulation in Minneapolis. This particular ice dam prevention project was in Edina.