Can ice dams cause roof damage? It’s hard to believe that icicles can cause roof damage, but ice dams are far more sinister than the innocent icicles that you find along your roof. Ice dams are formed when warm air rises up through your attic and melts the snow and ice on your roof.

When the roof gets flooded with water, it causes the water to drip down to the edge of the roof. Then it freezes, causing an ice dam.

Ice dams can grow incredibly large, putting a tremendous amount of weight on your roof. In fact, if the ice dam is making your roof leak, you can bank that the ice dam likely weighs a few thousand pounds.

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If you’re looking to learn if ice dams cause roof damage, along with information about how to prevent them, consider the following advice:

Can Ice Dams Cause Roof Damage? 

This is a common question that we hear a lot from homeowners throughout New England, especially this time of year when you get a mix of freezing rain and snow along with below-freezing temperatures.

If you have been wondering, “Can ice dams cause roof damage?” the short answer is YES: ice dams can cause roof damage. In fact, the damage might be even more extensive than you realize as these leaks can seep into your walls and cause mold damage.

The good news is that there are ways to prevent ice dams, even though some are more effective than others. But first, let’s talk about how ice dams form and how to know if you have ice dams.

How Do Ice Dams Form?

how ice dams form

It’s a cold day outside in Massachusetts and you have a lot of snow on your roof. You turn up the thermostat to warm up as the snow falls outside. Not long later, you start to feel a lot warmer in your home.

Hooray! But critical issues with your roof and attic will put a damper on your day with ice dams.

That’s because your attic space is now too warm. Your roof warmed up along with your attic and it’s now melting the snow while collecting in the gutters. It’s still freezing cold outside, so the water trickles down to your gutter system and re-freezes.  

Ice dams expand and cause shingles to lift, resulting in leaks under your shingles and into your home. Costly damages occur! 

How do You Know if You Have Ice Dams?

How do you know if you have ice dams on your hands? Check out these warning signs below.

Ice dams warning signs

  • They look like large icicles or chunks of ice that hang off your gutter system, much like the photo above.
  • You also may notice leaks in your attic.
  • Leaking windows is a misconception as many people think something is wrong with their windows but it’s actually the water coming down your walls into the window and/or frames.
  • Water also finds its way across ceilings into light fixtures.
  • Large snow glares at least 5″ thick
  • Termite infestation as these damp areas provide enough moisture to attract termites that go unnoticed can cause significant structural damage to your home. Don’t wait until the ground thaws out to let these pests do their damage to your home!

Two Ways To Prevent Ice Dams

Roof Ventilation Prevents Ice Dams

prevent ice damage

The most effective way to prevent ice dams is by ensuring two critical components are in place for your roof and attic.

  • Roof ventilation in your attic space. Even during the winter, you want airflow working its way through the attic space. It’s crucial to reduce attic moisture and escape the heat in your attic. Remember your attic should be the same temperature as it is outside! If the roof isn’t properly ventilated, this is a major culprit that causes ice dams to form.

Pro Tip:  Seal air leakage areas around recessed lighting cans, electrical cables, and vent pipes.

So, how do you properly ventilate your roof to protect against ice dams?

First, you must make sure there is a correct balance of intake and outtake vents to move air through the attic. The diagram below shows how air is brought into the attic by intake vents and pushed back outside by outtake vents.

move air through the attic

Image source: Green Building Advisor

With this intake and outtake process, you can be sure that your attic space remains at the correct temperature.

Two Crucial Types Of Vents Needed To Prevent Ice Dams

soffit vents


  1. Ridge Vents: These vents are outtake vents and installed at the ridge of your roof. The vents push cold air back outside and encourage circulation. 
  2. Soffit vents: Installed on the underside of your soffit, serving as intake vents that bring cold air into the attic.

Leak Barrier and Underlayment Prevent Ice Dams

The second reason why ice dams become an issue is because of bad or incorrect underlayment or leak barrier material.

  • When the ice dam melts, it can seep through your underlayment and lead to mold in your attic. In the worst scenarios, it can make the wood rafter beams rot. Yikes! It’s critical to have waterproof protection against ice dams, but not all New England homes have this setup. For example, older roofs use tar paper as an underlayment. It’s not rocket science to know that paper isn’t the right product to protect water from entering your home. We use Tiger Paw from GAF roofing which allows moisture to escape from your attic which provides an exceptionally strong layer of protection. While other roofers may only use 3’, we install 6’ of protection against water damage.

preventing ice dams

  • Roof deck protection, aka Ice & Water Shield, helps shield the roof against moisture infiltration. Protect your home by preventing leaks due to water damming in your gutters, wind-driven rain, and, damaging ice dams.  This is best installed in valleys and at eave and rake edges — the most leak-prone areas of the roof.

roof protection

Recap: If you are wondering, “Can ice dams cause roof damage?” the answer is yes.

As you may know, ice dams are a layer of ice that forms at the edge of a roof and prevents melting snow from draining properly. The melting snow seeps back up behind this dam and leaks into your home. If you don’t have proper ventilation, underlayment, and leak barrier this can cause ice dams. This can reak havoc on your home with water damage to walls, ceilings, and insulation. Take these necessary steps to ensure winter doesn’t get the best of your home.

Talk With Coastal Windows & Exteriors, The Ice Dam Experts 

How do we know if ice dams cause roof damage? After 10+ years in business, we are GAF certified roofing contractors who know how to install high-performance roofs!

Only 2% of roofing contractors achieve this elite status. Our roofs are engineered to prevent ice dams and all the damage that comes along with them. Don’t let winter get the best of your home…prepare now!

Contact us to rid of ice dams for good with new roof installation.