Wednesday, 13 February 2013

OH NO! It's an ICE DAM!!!!

Eavestrough, all home owners need them! However, if you thought this vital part of your home was safe from wrongful attacks and the blame game, you’d be wrong. All across Canada, the poor innocent and unsuspecting eavestroughs get wrongfully blamed for a wintertime malady called Ice Dams.

In wintertime, on a number of homes, Ice Dams occur. When people look up, they see a huge mound of ice accumulating on top of their eavestrough and roof, and they get mad and upset. Who wouldn’t? Roof top ice can cause damage to eavestrough, roof shingles and result in water leaks.

When the eavestroughs are covered in a mound of ice, they do look like the guilty party. But the truth is, the eavestroughs DO NOT cause Ice Dams. Dangerous quantities of ice will still accumulate, even without eavestroughs. It is easy to cast the blame at the poor innocent eavestroughs but they are not the root problem. That's just where the problem becomes visible. Blaming an Eavestrougher for an Ice Dam is like blaming the Plumber for a Sewage Back up!

The ROOT CAUSE of Ice Dams

When an attic is too warm in winter, it melts rooftop snow, even when outdoor temperatures are below freezing. As this water runs down the artificially warm shingles, it eventually hits the lower edge of the roof. Since there’s no heat underneath this location, the water refreezes, forming the start of an ‘ice dam’. After a few weeks of sub-zero weather, the thaw-and-freeze cycle has left behind a great big problem....a WALL OF ICE ON THE EDGE OF THE ROOF AND EAVESTROUGH!
See the you tube video below:

Ice Dams and your Home

The reason to take ice dams seriously is the damage they can cause to your house. If the dam is more than a few inches thick, it can trap and hold significant pools of water when things warm up during a thaw. Shingles can only keep water out of your home if it’s running downwards off the roof and into the eavestrough. Halt this downward flow and water can back up seeping into your attic, through your ceiling or around the top of the fascia board and into your house. DON'T BLAME your Roofer and DON'T BLAME your Eavestrougher. It just isn't thier fault.

Here are some pictures of Ice Dams:

1. Notice the wall of ice forming on the end of the eavestrough. It extends several feet back onto the roof.

2. The next picture shows the wall of ice is about 6 inches higher than the eavestrough!

This next picture is a home that has an ice dam but the picture is taken from under the soffit area. Notice how the water is beginning to travel backwards and it is coming through the soffit area.

The next is a series of pictures all of the same house.

First notice the right side of the house. Ice has formed on the eaves and has built up about 2 ft. back on the roof.

Next the left side of the house. Similar situation but look at the brick behind the over hanging ice on the right. The brick is wet. Water has already begun to travel backwards over 1 ft and is getting perilously close to entering the house.

Next, believe the unbelievable...Water has begun to enter the house in small quantities! This is the inside window sill. The water staining is visible although the water has dried. The window also lost its seal in this battle with the ice dam. The window is in need of replacing. The damage is comparably minor compared to some. In other cases, significant drywall damage can occur or worse, your favourite $1000 recliner chair can get soaked!

A friend recently shared with me a picture of her ice dam. This is a classic picture! Look at how the ice formed over the eavestrough without ever entering the eavestrough itself!

How to Battle Ice Dams

There are three possible solutions in battling ice dams:

  1. First increase insulation in the attic. You need to reduce heat migration into the attic from your living space, and less heat energy will be available to melt rooftop snow. You will also save money on heating costs. However, doing this does not guarantee you won't get an ice dam.
  2. Heat can also escape through air leakage. This is why preventing warm indoor air from travelling into your attic is vital. It doesn’t take much of a hole or crack or gap to allow heat to escape.. Start by looking at your attic access door. This is a popular spot for massive air leaks into attics. Two rooms ice dams love to form over are the kitchen and bathroom, for obvious reasons. The kitchen especially puts out a ton of heat because of the stove and other appliances.
  3. The third thing you need to do is increase attic ventilation. Boosting attic ventilation allows heat that does escape to be vented from the attic space via roof and soffit vents. Adequate roof vents and soffit venting is a must.

When all else Fails, One Last Ice Dam Solution

Solutions like those above aren’t always easy. Sometimes they’re not even possible in older homes because of how they were designed. That’s why, when all else fails, rooftop heating cables may be necessary.  Rooftop heating cables installed around the lower roof edge and eavestrough keeps them warm enough to allow water to keep flowing downwards, even when temperatures are below freezing. It’ll cost you more in electricity, but even that’s better than water entering inside your home. Icing cables do not cure the root problem, but they will resolve the nasty out come.

In conclusion. I encourage you to read this very well written and articulate article from the University of Minnesota:

and watch this very good video by Tim Carter of "Ask the Builder"

For all your eavestrough needs, contact The Eavestrough Company at or phone us at 905-966-2564.


  1. Thank you for this article. It was very helpful in understanding ice dams. We had an ice dam after the last big storm and water came into our kitchen. Your article helps us figure out things we can do to help avoid future problems.

  2. Rupa, I hope all works out well for you and that you find the source of the problem!


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