Ice Dams: Why Proper Attic Ventilation is Key!

With the winter months are upon us, you may experience another common culprit of poor roof ventilation: Ice dams.

Ice dams cause upwards of millions of dollars of property damage across the Midwest every year. Ice dams form when heat from the house escapes into the attic and warms the roof enough to melt snow on top. Because hot air rises, higher areas on the roof tend to be warmer than lower areas. Snow in contact with roof surfaces with temperatures above 32°F will melt. When that melted snow flows down to a colder part of the roof, it re-freezes. As this cycle of melting and re-freezing recurs, a ridge of ice develops and traps water on the roof. Often, that water will leak into the home which could damage walls, floors, ceilings, etc.

Now, there are a number of contractors that neglect air-sealing. It is, perhaps, the most crucial step in preventing ice dams. Warm air will always find a way to get through the ceiling plane and into the attic. Opal Enterprises installers are trained, tested and often checked up on, by GAF and their Master Elite program; putting you, the homeowners, mind at ease when those winter months approach.

A common misconception is that ice dams are related to gutters. Gutters do not cause or even increase the severity of ice dams. There are two types of people will tell you that gutters cause ice dams: people who don’t know the science behind them, and people who want to sell you a gutter system that supposedly prevents them from forming. A house with gutters can sometimes be prone to larger, thicker ice dams, when compared to a similar house that doesn’t have gutters.  Both houses will have ice dams, but a house with gutters will have a bit more ice along the edge of its roof. Simply because gutters stick off of your roof, which means that your roof has more overhang. The only hand gutters have in ice damming is, allowing the ice to crawl a bit further past the edge of your roof overhang; because gutters are essentially, an extension of your overhang. The more feet of overhang on your roof, the greater the potential for big ice dams forming; simply because the overhangs are the only parts of your roof that don’t have any attic space underneath them, to be heated with. 

When your roof is experiencing some symptoms of ice damming, you’ll want to get it tended to, quite quickly. With this you run into extra cost and finding a contractor suitable to do the work. Some contractors, who try to prevent future ice dams, actually make things worse, by adding more insulation. Sure it should kill any cure any thermal ill, however, the truth is that a bad insulation job can actually make it worse. By adding the extra and/or unnecessary insulation, it can increase the risk of ice problems by blocking the soffit vents and trapping heat and moisture in the attic.

 If you decide against spending the money on a contractor, know, the worst of all solutions is shoveling snow and chipping ice from the edge of the roof. People attack these piles of snow and roof ice with hammers, shovels, ice picks, snow rakes, crowbars, and/or anything heavy that will get through mess! The theory is easy; with no snow or ice, there is no leaking water. Unfortunately, this method threatens life, limb, and roof. Others take the “salt” solution and apply rock salt to the affected areas. Now, this very well may melt ice, but it also shortens the life of metal flashings and gutters. Although it may work, the common recommendation would be to avoid using salts to remove ice dams.

In theory, preventing ice dams is simple: Keep the roof surface cold. That means good air-sealing to prevent warm indoor air from leaking into the attic; enough insulation to prevent conductive heat losses; and adequate ventilation, to allow any heat that does make its way into the attic to mix with outdoor air before it warms the roof sheathing.