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Ice Dams On Houses – How To Prevent & Fix

18 Dec 2013, 11:47 am

If you’re an avid WeatherNation viewer, you’ve probably heard me (Aaron Shaffer @ashafferWNTV) talking about the joys of home ownership.  I just purchased my first home in early November, and am discovering quickly how the expenses and issues pile up.  The latest issue, and I’m still trying to solve this – as many of you likely are – is how to deal with ice dams.

This is an ongoing issue for me, so perhaps I’ll post an update at some point… but here is the general look of an ice dam:


Ice Dam: Image Courtesy of UMass


I, as many other homeowners do, found myself hoping/crossing fingers/etc. that ice dams would not be a problem for me, but alas that was not to be.

There are two different ways to sort through an ice dam.  There are ways to “beat them” after they occur, and there is ice dam prevention.

Let’s start with prevention, since that is the cleanest approach.

To know how to prevent an ice dam, you need to know why they occur.

It all starts in your attic/inside your roof or home, and ends on the eaves of your house.  What is an eave, you might be asking?  Well – see below for that:


(Thanks to for this schematic)

What happens, particularly with poorly insulated (typically older homes), is that you get heat escaping through the attic, the ceilings, etc.  My house is a 1906 story-and-a-half style home, meaning the attic was partially converted into living space.  As such there are areas with limited space for insulation that would separate the outside portion of the roof from the heat inside the house.

As heat escapes, it causes snow to melt.  That melting water then reaches the eaves of your house (that is why it’s important to know what those are), where they aren’t heated by anything.  See in that image above how the eaves aren’t directly touching any source of heat?  That is where the re-freezing occurs.  This time as ice.  Not good.


So how do you prevent them?


Insulation is the key.  If you can keep the interior portion of your roof from letting out heat, you prevent melting, which then keeps the snow all as snow.  Another method I’ve seen is to blow cold air into your attic, thus keeping temperatures on the outside AND inside roughly the same.

You can also use heated wires that you’d install ahead of time, and then allow the warmth to melt the ice away as it forms.

Another step would be to brush away snow with special brushes/roof shovels to keep snow away from the eaves of your home.

Here is an example of something I’ll be buying shortly, this one from Home Depot – but you can likely buy these at any major hardware store.

A roof shovel/roof rake:


What do you do if you already have ice jams?


In my case I already have them formed/forming.  So I need a solution.

The obvious idea is to hack away at the ice with a hammer/chisel/etc.  Don’t do that.  It can cause injury, but it can also damage your roof.

Ice melt can work – but don’t use salt.  Products for melting roof ice exist, and I’ve been researching some of these for my own uses.


Salt-filled pantyhose is another method of melting ice dams.  Although I don’t know much about it, I’ve heard you’d leave it on the edge of the roof for an extended duration.

Finally, I’ll leave you with a funny & well-executed video of why you don’t want to use a blowtorch to melt ice dams (besides the obvious reasons you’d probably want to avoid it).



Stay tuned!

WeatherNation Meteorologist Aaron Shaffer @ashafferWNTV

One response to “Ice Dams On Houses – How To Prevent & Fix

  1. I just moved to a cold climate and had no idea about ice damming. I wouldn’t have know that it is a good idea to keep the interior of the roof insulated so no heat escapes. I will make sure to keep the heat out from the upper portion of the home. Hopefully this helps!

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