How to Prevent Icicles on Gutters and Roofs

large icicles hanging from a gutter

Last Updated: February 5, 2024

While the winter wonderscape is undeniably beautiful, it can also be treacherous, as freezing temps, snow, and ice, can wreak havoc on homes. Even something as innocent as icicles can grow and damage your gutters with their weight or pry under your shingles and retreat into the attic, where the ice often melts to cause more damage in its water form.

All of this happens because of ice dams in the gutters. Why do icicles form on gutters? It’s quite a process.

When excess heat leaks from the roof, it melts the snow. As the snow trickles down, it touches the cold metal on the gutter and instantly freezes. The ice continues to build until the passage is completely blocked. If the gutter is clogged before this buildup, the blockage happens even more quickly. The dam doesn’t stop the ice from building, though. Instead, it starts to spill over the side, forming large icicles. It also pushes back against the roof and can dig under the shingles.

What Is an Icicle?

Icicles hanging from the roof of a house

Let’s talk about icicles, those cone-shaped shimmering sticks of frozen water that hang from the side of your rooftop and gutter. Icicles on a roof need water to form, along with a combination of sunshine or heat, contrasted at different times with below-freezing temperatures. They take their shape when water starts to melt and then drip off the side of your roof in sub-freezing temperatures. The thawing and then refreezing process creates those shimmering spikes of frozen water that look pretty but can pose problems.

Icicles are different from ice dams. Instead of dripping off the side of the roof, ice dams form and build up toward the edge of the roof. Ice dams can seriously damage your shingles and roof decks, as well as cause leaks that could make their way inside your home. But if you properly take care of ice dams and icicles, you can prevent these worst-case scenarios.

Why Do Icicles Form on Gutters and Roofs?

Icicles hanging from a gutter on a roof

So why do icicles form on rooftop gutters? Icicles on a roof can be a perplexing sight. After all, how can water melt during sub-freezing temperatures? The culprit is your home’s insulation.

Poor insulation is the main reason why icicles form on gutters and roofs. Heat rises, which means that most of the heat in your home is making its way to your roof. If your home has poor insulation, then it’s not keeping the heat inside your home; it’s going straight to the roof and causing snow to melt. Of course, sunshine is also a big part of the thawing process.

The following can cause icicles on a roof:

  • Poor insulation in the attic: As noted earlier, heat rises, and if the attic has poor insulation, the temperature won’t be distributed evenly.
  • Chimneys, plumbing stacks, and dryer vents: Features such as these release heat, causing ice and snow to melt, thaw, and start the refreezing process.
  • Quick changes in temperature: You can’t do much about rapid fluctuations in weather. Unfortunately, these rapid temperature changes can create the perfect storm for icicles to form.

Why Icicles Pose a Threat

Icicles are a sign of winter, and they do have their charm. They aren't as damaging as ice dams are, but can pose a threat to passersby and the gutters of your home. Having icicles growing on the side of your home doesn’t necessarily mean you have ice dam formations. But icicles can still be hazardous, especially if they break off and land on someone. These sharp, heavy formations have caused countless injuries and even deaths.

It's best to keep children away from icicles. Don’t ever eat or drink the water if they’re melting. Icicles are dirty and might contain lead, bird poop, tar, and pollution from car exhaust.

Icicles on roofs can damage the roof itself. They can also cause water damage, as well as break windows, electric lines, or gas meters.

How to Stop Icicles from Forming on Your Roofs and Gutters

Person removing snow on the roof after snow storm

How can you prevent icicles on a roof? Will gutter guards help? Gutter guards do a great job of keeping debris out of the gutter. No debris means water can flow freely, but it doesn’t necessarily prevent water from freezing. However, when there is less water to freeze, ice dams won’t get any bigger. Also, note that metal guards can freeze during winter, and icicles may form.

The good news is that you can learn how to prevent icicles on roofs and gutters. You can be proactive against ice dams as well through the following:

  • Clean Gutters: Do clogged gutters cause ice dams? They can certainly contribute to the issue. If the water has no place to flow, it will dam more quickly than if there is a passage for the runoff. That’s why cleaning your gutters in the fall can help prevent icicles from forming.
  • Proper Insulation: One of the best ways to prevent icicles on gutters is by minimizing the heat leaking from the roof with proper insulation. Insulating the attic floor will keep the heat in the home where it belongs. Some insulation under the roof could also help as a barrier.
  • Sealed Air Leaks: Even if you have your attic properly insulated, leaks from your chimney, flue, or other vents can provide enough heat to melt the snow on your roof.
  • Heat Tape: Apply heat tape to the gutter and crisscross on the edge of the roof. This tape plugs into an outlet and uses electricity to generate heat. This heat will keep snow from forming back into ice before it runs off the gutter.
  • Snow-Free Roof: By using a snow rake or a push broom to clear the snow from your roof, you can minimize the chance of snow melting and trickling into the gutters to freeze.

How to Melt Ice Dams in Gutters

Icicles hanging from gutter on a roof

Perhaps the ice dams have already formed and are growing. How do you clear them?

  • Use Calcium Chloride Ice Melter: Fill old pantyhose with a calcium chloride ice melter and lay it on the edge of the roof across the gutter. The ice will start to melt.
  • Don’t Use a Hammer or Shovel: Don’t try to knock the ice loose with a hammer or shovel. Forcefully breaking the ice dams will only cause damage to your gutters and roof.
  • Don’t Use Salt: Discard the thought of melting it with salt. Sodium chloride, or table salt, is extremely corrosive. It would wreak havoc on your roofing, siding, gutter, and downspouts sooner than it would melt the ice.
  • Blow in Cold Air: If you have an ice dam leaking back into your attic where it melts and causes water damage, you can quickly stop the water with a box fan. The fan will equalize the temperature between inside and outside, cooling the attic and forcing the water to chill enough to freeze. It will stop the leak, but there will still be repairs before it’s fixed.

Call in the Pros!

Now that you’re fully informed on icicles and ice dams, what about the rest of your winter issues? The season presents a range of challenges on your property, from snow-covered driveways to icy walkways, which can be not only frustrating but also dangerous.

When you need help with snow and ice, find your local The Grounds Guys®. Our snow and ice management services include ice melting, salting, sanding, snow clearing, and more. We offer free estimates, and all our work is backed by the Neighbourly Done Right Promise™, which means that it’s done right the first time.

Don’t face the ice and snow alone. Contact us today!