May 18

Everything You Need To Know About Ice Dams (And What To Do About Them)

After storms or heavy snowfalls, large blocks of ice can form above the edge of your roofline, causing water to enter your home and damage to your home’s exterior. This build-up of snow on your roof is called an ice dam.

What Are Ice Dams?

Ice dams are masses of ice that form at the edges of your roof and hang over the edge forming large cascading icicles. These icicles may look pretty, but many don’t realize that ice dams can cause significant damage to your property.

Ice dams canweigh hundreds of pounds, which risks structural damage to your eaves and can even rip them off. But the real problem is that a buildup of ice on your roof’s edge can block meltwater from flowing into your eaves and away from your home.

Water that’s backed up and sitting on your roof will more easily get under your shingles and inside your home. The risks to your home include damages to your roof, gutters, drywall, paint, and insulation.


How Are Ice Dams Formed?

Ice dams form when the roof’s upper edge or ridgeline is above freezing and the lower part near the edge is below freezing. The upper area melts snow that runs down the roof where it re-freezes at the lower edge and builds up a wall of ice that then prevents water from flowing off of the roof.

The solution to preventing ice dams is simple in theory: if the air in the attic or against the bottom of the roof can remain below freezing, snow won’t melt and supply the water needed to form an ice dam. Ice dams can be prevented by providing better insulation and ventilation.

Here are some of the ways you can prevent and remove ice dams from your roof.


Quick Ice Dam Prevention Measures

Calcium-Chloride Sock

Calcium Chloride is the same stuff we use to melt the snow on our driveways and sidewalks, and it can be an effective temporary solution to melting a channel through an ice dam that has already formed.

However, you need more than just a sprinkle to get through a thick ice wall. The best method is to fill long socks or pantyhose with the granules and position them vertically over the dam, with the sock hanging a few inches over the roof edge. The sock will be visible and won’t look pretty, but it’s a quick measure to remove the dam.


Keep Your Gutters Clean

One of the easiest ways to prevent ice dams from forming is to ensure you’ve cleaned out your gutters after the leaves have fallen. If your gutters are clogged, water will have nowhere to run and get stuck.


Rake Your Roof After Heavy Snowfall

Ice dams form quickly after a fresh snowfall as the new layer provides insulation trapping in heat. You can pick up a cheap roof rake with an extension to gently remove freshly fallen snow from your roof. Try to rake at least 4 feet of snow from the edge.

Raking is the only safe way to get the snow off of your roof; never get onto your roof to remove snow during winters. When raking your roof, be careful not to rake too hard, or you risk damaging your asphalt shingles and creating new areas for water to get inside.


Chip Off The Ice

It’s worth repeating – climbing on the roof to remove ice dams is incredibly dangerous. But if you have an extension ladder, you may be able to reach your eaves and chip away at the ice dam with a chisel, hammer, ice pick, or hatchet. You don’t have to remove the entire ice dam as only a small opening is needed to allow a channel of water to flow through. But this is a temporary fix requiring the process to be repeated frequently until you address the root cause of the problem.

Permanent Ice Dam Prevention Measures

Ventilate The Eaves & Roof Ridge

It may seem counterintuitive, but a well ventilated and cold attic will generally prevent ice dams from forming. This is because cold outside air circulating under the roof deck or in the attic ensures the roof remains below freezing, meaning that the snow cannot melt and form ice dams.

Ridge and soffit vents help with proper ventilation of cold air under the roof. Placing baffles at the eaves holds back the insulation a few inches and ensures there’s a path for proper airflow.

Added Insulation & Closing Attic Bypasses

One of the largest sources of a home’s heat loss is through the ceiling and attic. The floor of an open attic or ceilings of living spaces must be well-insulated. Uncapped or unsealed attic hatches, cracks around light fixtures, gaps in drywall, or any other ceiling penetration all let out heat through the roof and contribute to the formation of ice dams.

Sealing these gaps, however, can be difficult as you need to climb into the attic and plug leaks with calk or other methods. Covering your attic hatch with a foam board held together with a strong aluminum tape will seal the openings and prevent heat loss. An added bonus to sealing and insulating your home is the energy savings on cooling and heating bills!



Make sure that any exhaust ventilation from sources like washers and dryers, kitchens, and bathrooms all lead outdoors and away from the house, but never lead up through the soffits where the continuous hot and cool air condenses and freezes.


Waterproof Underlayment

If you are building a new home or replacing your roof, you should ensure that a waterproof shingle underlayment is put in before your shingles are installed. This barrier is completely waterproof and prevents any backed up water from getting inside your home.

Shingle underlayment won’t prevent ice dams from forming, but they are an important last line of defense against water penetration if they do.

Call A Professional Roofing Company


If you need help removing ice dams and fixing the problem that’s causing them, your best bet may be to call in professionals. Professional roofing companies are insured and qualified to provide these services safely and effectively. They’ll have the experience to assess and determine the exact nature of the problem and recommend the perfect solution for your home.

Finding the source of your ice dams and removing them yourself can be difficult and dangerous. Don’t risk further damaging your home or yourself by attempting to solve the problem yourself.

RELATED – 7 Warning Signs You Need To Replace Your Roof


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