Why Are Icicles Forming on Your Siding? (+ How To Fix It)


The quiet beauty of snow can be calming. Icicles on tree limbs are pretty, but icicles on the siding don’t look right. So why do icicles form on siding, and how can the problem be fixed?

Icicles form on the siding because ice dams on your roof are trapping snow. When the snow melts, water leaks behind the siding. As it freezes again, it expands, creating the icicles you see. To prevent them, a homeowner needs to stop warm air from coming into the attic.

Even though icicles on your siding might seem like a minor annoyance, they are a sign that water is behind the siding. This water can lead to rot and mold, so it needs to be investigated and taken care of. Keep reading to learn what causes the icicles and how to prevent them.

What Causes the Icicles on Your Siding?

The cause of icicles on your siding is snow being trapped by dams on the roof. These dams form on the eaves, where the temperature is coldest. These bands of ice can trap snow, which then turns to ice. As warm air from the attic rises, it melts the ice on the top of the roof.  

  • If the temperature near the eaves is cold enough, snow builds up. 
  • Once the snow turns to ice, additional water pools behind the ice dam.  
  • With the next wave of colder air, this water turns to ice.  
  • If the temperatures remain too cold to melt the snow from above, the warmer air coming from heat loss in the attic melts the snow from underneath.   
  • The melting water becomes trapped, turns into ice, melts again, and begins to travel under the roofing. 
  • If it finds a gap, the melting water drips into the wall cavity.
  • Icicles form when the water drips down the exterior wall.

The irony is that the ice dams and icicles are not caused by snow or extreme cold but by a warm attic. Fixing the problem permanently means you must keep your house warm but your attic cool. 

Ice dams and siding icicles tend to build on the north and east sides of houses. And if you have a home with an attached unheated garage, ice dams won’t form over it since there isn’t enough heat.

Should you want a visual demonstration of the process, check out this video:

How Do You Eliminate the Problem?

To eliminate the problem, you will need to brush the snow off your roof before it has a chance to freeze. However, this is a temporary fix. To keep the problem from recurring, you must better insulate your attic.

Removing the layer of snow is an easy but temporary fix. A snow rake allows you to “rake” snow off a roof while you stand safely on the ground. A good snow rake is lightweight, reaches onto the roof, and has a soft “rake” that won’t scratch the shingles. 

The Eversprout Roof Rake (available on Amazon.com) is one such rake. It extends up to 12 feet, has a soft foam pad, and weighs only 1.5 pounds. However, like other roof rakes, it only works on snow removal.

When using a snow rake, do the following:

  • Use it on soft snow, since snow rakes cannot remove ice.
  • Clear the snow from several feet past where the roof and external walls meet.
  • Do not climb a ladder.

It is not necessary to remove all the snow. The goal is simply to prevent the formation of ice dams.

What To Do if an Ice Dam Has Formed?

If an ice dam has formed, don’t panic. Since the problem is caused by water pooling behind the dam, you need to create a channel so the water can flow down.

A commonly used solution is to ice melt or rock salt. However, just sprinkling it on the ice won’t be effective. Doing that will simply create pockmarks.

Instead, the ice melt needs to be bundled together. To do that, you need a stocking and ice melt (rock salt will also work, just not as effectively). 

Pack the knee-high stocking with ice melt and tie the stocking end closed. Then place the ice melt “snake” on the ice pack, being sure to lay it on the ice dam perpendicular to the gutter. 

Give the ice pack a day to melt a channel for the water to drain away. 

Do not try to chip or scrape the ice away. If you chip or scrape the ice away, you might damage the roof. Even if your preferred chipper breaks through the ice without striking directly on the roof, the chipper’s blunt force can cause damage to the roof.  

Not to mention you’ll be standing on a ladder perched against an icy gutter and in soft snow or ice.

Pressure washing has its own set of problems. Shooting pressure onto the roof can compound the problem because it damages the granules on the asphalt shingles. If not done correctly, additional water can be sent under the shingles. This compounds the problem that caused the icicles in the first place.

How To Prevent Ice Dams?

To prevent ice dams, you need to insulate your attic. Depending on the shape of your insulation, you might be able to do it yourself. However, it can be a labor-intensive job best left for professionals.

Consider possible ways that warm air can leak into your attic:

  • Chimney chase ways 
  • Wiring that is run into the attic
  • Plumbing vents
  • Air leaks

Insulation experts use infrared thermometers to identify where the leakage happens to isolate the problem.

Sometimes the insulation itself is the problem.

  • Missing insulation. Sometimes a builder on a new home will leave an area uninsulated. Or the insulation has fallen. This is easily fixed.
  • Inadequate insulation. The eaves are not high enough for adequate insulation installation in older homes. Simply adding fiberglass insulation won’t solve the problem. Instead, the insulation needs to be pulled back so closed-cell spray foam insulation can be used to seal the eaves.
  • Wrong type of insulation. Although fiberglass insulates well, improper installation can cause air leaks.

To see if this is a DIY project, invest in an infrared gun, such as the Milwaukee 10:1 Infrared Temp-Gun (available on Amazon.com) to see how much air leakage you have in the attic. You might be lucky and find just a little. However, the chances are that if ice dams are forming on your roof, it’s not a one-day-and-done project.

Bottom Line

Snow’s calming effect can be partially explained by how well it absorbs sound. But there is nothing calming about seeing icicles on the side of your home. If they appear, the snow is quietly damaging your house.

Recent Posts