US Inspect US Inspect

What is an Ice Dam? And Why Don't I Want One?

Icicles on your home in the winter can be charming, but an ice dam is anything but. What the heck is an ice dam? Why don't you want one and how can you prevent them from forming?? You'll find everything you need to know here:

Weather conditions must be just right for ice dams to occur, but when they do they are potentially destructive to your roof system. Ice damns can cause gutters to give way, can damage shingles and cause interior leaking. The time to prepare for ice dams is in the summer or fall, before the onset of winter weather.

Ice dam

What is an ice dam?

 An ice dam is created when heat rising from the interior of your home collects in the attic, warming the underside of the roof decking, except at the eave area, and begins melting the snow. The meltwater runs down the slope of the roof, only to refreeze at the colder overhang. Subsequent runoff, having no place to drain, backs up under the shingle and into the interior of the home. Staining is often found in the interior of the home on the ceiling and near exterior walls.

What can you do about ice dams?

Before we talk about what you can do to lessen the probability of ice dams, lets talk about what you should not do.

  • Do not begin by bringing out your ladder, hammer, and shovel and attempting to knock and dig away the dam. You are not only endangering yourself, you are likely to create an even bigger leak issue than you have currently.
  • Do not throw salt or icemelt on the affected area. Deterioration, shingle wear and tear, and damage to the environment are all negative side effects.

So, what should you do if you discover you have an ice dam issue?

  • The quickest way to stop the leaking is to bring down the temperature in the attic. You might have to install a temporary box fan in the area of question.
  • Another option is to purchase or construct a long handled aluminum roof rake (with wheels) to gently pull off the snow without damaging the shingle. One manufacturer who specializes in snow removal and roof rakes is Avalanche.

It's important to know that just because you have ice dams doesn't mean you have a faulty roof and that roof repairs are necessary.

How can I prevent ice dams in the first place?

Here are some ideas to think about during warmer weather to lessen the effects of ice dams:

  • Consider flashing at the gutter area and eaves. Various types of flashing (drip edge, sidewall, kickout, etc) can be designed with water diversion in mind.
  • Deicing cables can be installed along the edge of the roof, and in the gutters and downspouts.
  • Maintaining a cold roof will lessen the chances of ice dams forming. To achieve this condition, the attic floor is overinsulated and the attic is overvented. This lowers the temperature in the attic and lessens the flow of snow melt.

Take time to study your roof now and identify potential problem areas to prevent dams before they start!