More snow, beware of Ice Dams

With these storms, I get many calls about water seeping through the walls or ceilings from melting snow.  This is caused by ice dams. They generally appear after a heavy snowfall during an extended period of cold temperatures. Because ice dams occur on roofs buried in snow, few people actually see them, let alone understand their causes. The only time people think about them is when they occur, which is about the only time that almost nothing can be done.

 

What are Ice Dams?

 

Ice dams are literally dam-like buildups of ice on a roof. They normally occur at the edge of the roof but can occur higher up under certain circumstances.

 

The ice itself is not a problem. The problem is caused by melting snow can form a pool behind the dam. Most roofs are very effective at shedding water. Very few roofs, however, are designed to cope with pools of water. Water backs up behind the ice, seeping up under the shingles until it finds its way through the roof to the attic and living areas below.

While usually temporary in nature, the massive roof leaks the dams cause can wreak all kinds of havoc with wiring, drywall, paint, carpet, flooring and interior furnishings. Ice damming can also cause problems for your exterior siding and the wood and insulation behind it.

What Causes an Ice Dam?

 

Ice dams occur most often when we get heavy snow followed by below freezing temperatures, but they can occur with just an inch or two of snow. Some part of your roof warms up enough to melt the snow. The melt water flows down to another part of the roof that is cooler, and the water refreezes. The ice forms a small dam that builds up slowly as more melt water refreezes. Eventually, water backs up behind the dam and works its way up under the shingles until it begins to leak through the roof into the living space below.

There are four main causes of ice damming, and the latter three we can actually do something about.

1. Weather
2. Household heat escaping to the attic
3. Uneven roof temperatures
4. Roofing underlayment that water can penetrate

Preventing Ice Dams

Ice dam prevention is best achieved in three ways: 

1. Attic insulation
2. Attic ventilation
3. Proper re-roofing

There are many sources of information  on properly avoiding Ice Dams.  Some insurance policies will cover the damage, but it is subject to the deductible.  Give me a call if you would like some more information about how to prevent ice dams.  888-900-2173