What Causes Ice Dams – Signs And Roof Backup Problems

What is an ice dam on a roof? Are you wondering how the ice dams in your roof were formed?

If you are, then you’re reading the right article.

I’ll be telling you what causes ice dams, where they can form, and what you can do to avoid problems with ice backup on roofs.

Keep reading, as I’ll be discussing everything you need to know about roof ice dams.

Ice Damming Causes

As the name implies, an ice dam is a solid formation of refrozen water (usually from melted snow) that prevents water from flowing off the roof through the gutters.

Since the water cannot flow away, it will either be pushed back under the roof shingles or refreeze to form a larger ice dam.

Ice dams are most directly related to cold weather. They are just as common as the winter season itself.

It could build up on your roof every year if you do not take preventive measures.

  • Where Can Ice Dams Form?

Ice dams can form in different areas of your roof. These include the eaves, the downspouts, and the gutters.

As for those downward pointing ice formations by the edges of your roof, those aren’t ice dams, they are called icicles. However, the conditions that icicles need to form are the same as ice dams.

So if you see icicles, then you’ve probably got an ice dam formation on your roof.

What Is Ice Damming On Roof?

Have noticed blocks of ice forming around your roof’s eaves, gutters, and downspouts? Well, those are roof ice dams, and they are in no way good for the well-being of your home.

These icy formations have a lot of weight, and they are usually found forming along your roof’s eaves and gutters.

Ice dam formation on your roof is caused by a combination of warmth and cold.

Ideally, all parts of your roof should maintain the same cold temperature to ensure that ice dams do not form.

If one part of your roof is warm, it will melt the snow around it. And as the melted snow makes its way down, it will make contact with the cooler eaves and refreeze. And that is how ice dams form on your roof.

So what causes ice damming?

The more the snow melts, the more refreezing action will take place, and the larger the ice dam formation will be.

I’m sure you’re wondering what causes the snow to melt in the first place. Well, sunlight can cause snow to melt, however, the sunlight is evenly distributed across the roof.

This means it won’t just be heating only a few sections of the roof, it will heat all sections of the roof.

This makes it less unlikely to cause roof ice dams, being that the eaves where the refreezing action usually takes place are also too warm.

There’s a second reason for warmth on your roof, and that’s your attic.

Attics are just under the roof of a home, and there is a lot of heat stored in that area. The heat can escape through the ceiling and into the roof, and any patches of snow around there will begin to melt.

Sadly, the heat from the attic isn’t evenly spread across the roof, which means there are still some cold parts. It is when the melted snow flows to the cold parts that the refreezing action takes place.

Some of the water freezes on its way down, and that is why you see the formation of icicles.

What Causes Ice Dams In Gutters?

The principle for ice dam formation on the roof is basically the same as ice dam formation in gutters.

Once heat melts the snow on your roof, the slush can flow into your gutters. Remember, the gutters are there to channel roof water away.

However, the gutters will be too cold to continue the flow and will begin freezing the water instead. The more melted snow that flows into the gutters, the bigger the gutter ice dam becomes.

This is not good for your gutters, as the weight of the ice dam can pull the hinges off and cause your gutters to fall and get damaged.

  • Can Gutters Cause Ice Dams?

Well, the gutters aren’t responsible for the formation of ice dams.

Even though it serves as a formation site, it is the melting and refreezing action of snow that actually causes the ice dam formation.

How To Identify Ice Dam On Roof

Identifying an ice dam on your roof is actually very easy.

Although you may not be able to see the ice dam from the floor where you stand, there is another clear pointer that ice dams have started forming on your roof.

Icicles, which are large drops of melted snow that have refrozen on their way down, require the same conditions as ice dams before they are formed.

So if you cannot see the ice dam itself, the icicle formation is a clear sign that the conditions are right for an ice-dam build-up.

What you can do to get a visual confirmation is to get a ladder and climb up your roof. Take a look into your gutters and eaves to see if the ice dams have begun to form.

Of course, climbing up an ice-cold ladder and walking around a frozen roof isn’t something that I’d consider safe. So if you want to inspect your roof for ice dams, then contacting an ice dam removal professional would be your best option.

They are well trained in roof climbing and have years of experience inspecting roofs and removing ice dams.

Problems With Roof Ice Dam

The major problem with roof ice dams is that they can cause a lot of damage to your roof, rip off your gutters, and burst open your downspouts.

Ice dams can also cause problems indoors, it is known to push some melted snow under your shingles, which will eventually make its way through your ceiling.

Let us take a quick look at just how problematic roof ice dams can be.

  1. It can damage your shingles

Shingles may not be the most expensive things in the world, but that doesn’t mean you’d like to waste money replacing them. Well, if you do not handle your ice dam problem quickly, then you may just find yourself in the market for shingles!

When ice dams stop water from flowing down, it gets pushed back under the shingles. The excess water can soak up the shingles and can also refreeze.

Keep in mind that shingles aren’t made of tough materials, and they can be very brittle when exposed to cold. Shingles with frozen water around it can begin to crack, and you will need to replace them.

  1. It puts extra weight on the roof

Another major problem with roof ice dams is that they are too heavy, and they place unnecessary weight on your roof.

Let’s not forget that ice dams are hundreds of gallons of water that have taken an icy form. Imagine how heavy a gallon of water is, now imagine the kind of weight a large ice dam is placing on your roof!

Such weight can cause some parts of your roof to cave in. And this can also affect your gutters too, as the weight can cause them to rip off their hinges and fall.

  1. It can damage downspouts

When ice dams form inside your downspouts, any water trying to flow through will be blocked off. Even worse, it can refreeze and form a larger ice dam.

When the ice formation in your downspouts gets too big, it will begin to expand the pipe, and it will only be a matter of time before it bursts open.

  1. It can mess up your interior

The water backed up by roof ice dams can pass through the openings of the damaged shingles and enter your home.

This can leave your ceiling, floors, and drywall damp. And this can lead to the growth of dangerous mold.

How To Forestall Ice Dam Problems

Now that you know exactly what causes ice dams to form, here are some steps you can take to stop that from happening.

  1. Insulate your attic

Attic insulation is one of the best things you can do in the fight against ice dam formation.

Once your attic has been insulated, the heat will be trapped inside and will not be able to escape through the roof. A lack of warmth on the roof will mean there will be no melted snow.

  1. Keep your gutters clean

This may seem like an ineffective approach, but trust me when I say it works.


Melted snow isn’t actually 100% liquid, it’s slush. And this means it cannot flow as fast as water. If your gutters are filled with debris such as bird nests, leaves, sticks, and stones, then the snow slush will flow slower, allowing more than enough time to freeze.

On the flip side, if your gutters were free of debris, the snow slush would have a better chance of flowing out faster, hence reducing the time it has to freeze in the gutter.

  1. Install heat tapes

Heat tapes can be used to keep your roof warm and eliminate then refreezing cycle. They are long cables that produce heat when plugged into an electrical outlet and turned on.

There are more advanced heat tapes called self-regulated heating tapes, and these types are the best for you.

This is because it can adjust the amount of heat it produces according to the outdoor temperature.

Self-regulated heat cables will become warmer when the outdoor temperature drops and will become cooler when the outdoor temperature rises.

Heat tapes should be installed in the areas where ice am formation is most likely. This should be along your eaves and inside your gutters.

Speaking of gutters, there are special kinds of heat tapes that can be placed inside them to guard against ice dam formation.

Being that the gutter is extremely cold, this type of heat tape is covered with copper or aluminum material, which radiates the heat coming from the heat cables.


Here, we have discussed roof ice dam causes.

Roof ice dams are actually good-looking, especially when paired up with snow fresh white snow. However, looks can be very deceiving, as roof ice dams cause nothing but trouble.

If you’ve never lived in an icy environment before, then this may be your first time hearing about roof ice dams.

It’ll be fair to say that the more knowledge you have about roof ice dams, the better you can prevent it from forming.

Knowing what causes ice dams is great, but preventing the formation is more important.

A roof ice dam is problematic in so many ways. It can damage shingles, burst downspouts, and leak into your home.

Ice dam damage will cost you thousands in repair or replacement, so be sure to prevent it at all costs.

Take care!

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