Snow has blanketed most of the United States all winter so far. Businesses and homeowners are concerned about the impact this weather will have on their homes and businesses.
Winter weather extremes such as the events that many areas of the United States experience now, don’t just pose a danger to rooftops; they pose a danger to surrounding property and interior walls, ceilings, and even floors. When there are temperature changes on different parts of a roof, ice dam formation is almost inevitable. Recent television news stories showed footage of roof collapses, particularly in hard-hit New England, all of which resulted from heavy snow accumulation on rooftops.
What are Ice Dams?
Ice dams form when water from melted snow at the top of a roof, pools along the edges of the bottom of the roof’s pitch (along the eaves,) refreezes. This continues to happen all winter, and the more snow there is, the greater the potential for very serious problems. Ice dams typically form when snow covers most of a sloped roof. These large frozen mounds can inhibit draining through residential and commercial gutters.
What Causes Ice Dams?
Ice dams can only develop when three conditions are present. There must be snow – and lots of it. The second condition is a source to melt the snow. The third requirement is sub-freezing temperatures that cause the water to refreeze. When the cold temperatures refreeze the melted snow, the buildup of ice creates a dam that prevents water from draining off the roof.
This is a vicious cycle because more snow causes more snow to melt, and most of the water freezes again, creating large ice accumulations along the eaves and ice damming gutters. As the layer of snow that is closest to the roof keeps melting. The ice dam creates a blockade that stops water from going into the gutters and draining off the roof.
Ice Dams Can Cause Serious Problems
Most people have seen ice dams without realizing what they were or how they formed. One telltale sign that a building has an ice dam problem is the sight of icicles dangling from the eaves of the roof. The potential problems that ice dams can cause are very serious.
How to Prevent Ice Dams from Forming
The Insurance Institute for Business & Home Safety offers some excellent suggestions for ice dam prevention.
On sloped buildings, removing snow minimizes the potential for ice dam formation. Keeping snow off a roof will eliminate the problem of ice damming gutters. On a single story building, a roof rake is useful for removing snow. On buildings where the rake won’t reach the roof while someone is standing on the ground, contact a roofing contractor.